I am getting ready to embark on a home addition. It will be 10'x5' and will be three stories high. The rest of my home has a flat roof and for consistency sake we would like the addition to have a flat roof as well. Can anyone help me figure out how to frame a flat roof?

The addition will be tying into a brick house, so on one side the rafters will be attached to a ledger board, on the other side they will rest on a double sill plate created by a new wood framed exterior wall.

First, given the addition is small, what size rafters do you suggest, will 2x10s suffice? What about 2x12?

Second, what sort of slope is necessary for a flat roof?

Finally, how do you frame it to get that slope?

Hi Stubits. This has to be the smallest 3 story addition I have heard of in 30+ years of building.

So to answer the floor joist size. This will depend somewhat on the size of the floor joist you have on the main structure so the door to each floor works in elevation. Unless you don't care to maintain the same ceilings heights the main house has.

A 2x8 16 o.c. at 5 feet is good if the code allows it


As far as the Roof pitch, a 1/4 per foot min is what I go by for "flat" roof. I also you 0.60 rubber for for the flat.

Now here's what you may want to think about for the roof. How much insulation thickness you need and it needs to vented.

You ask how to bulid the flat roof. This depends on the adjoining roof beside it, and which way it slopes. You could continue the same slope being the add is only 5 feet wide. You could knee wall it above the other flat roof and pitch it either way. With knowing the specifics of the old off heights or slope I'm just giving ideas here.

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This is great info! I'd rate your answer, but the system wants to me rate someone else first.

It is a small addition, but just right for us, really. It will help us gain an extra 1.5 baths, which is all we really need.

As for the floor joists, we are actually planning on using 2x12s throughout, mostly because there will be lots of plumbing, and as such, unfortunately some holes will need to be drilled in the joists, not too many, but a couple, for sure. We aren't too concerned with maintaining ceiling heights, as our ceilings are rather high, but we are working to make sure to keep the doors at the same elevation. Thanks for all your advice on those points.

As for the roof itself, we are looking for R-36 level insulation. Our current roof isn't vented (it's a 75 year old home). How are flat roofs typically vented? Please see the accompanying photo, we are effectively enclosing the dog ear area of the home's footprint. I guess what I am trying to figure out is specifically how to frame the flat roof. We'll install ledger boards along the long brick wall for the floor joists and I am thinking I will do the same for the roof, right? Given that the roof will slope down over 10', the base of the roof will be approximately 2.5" lower than the top, right? I think I understand how to do that on the ledger board, but how does that work on the other side, where the joists rest on the stick framed wall? Do I notch the joists slightly as they go down?

I've never built a roof before, let alone a flat one, so any help would be much appreciated! I will hire a rougher to actually finish the roof off, but I plan on framing it myself. The roofer will flash it, etc.

Thanks!

After I posted I thought about possible mechanicals in the floor joist.

As far as venting the flat roof, here's s a site that has vents for intake and exhaust. One vent pushes air in and the other takes it out.

Rooftop System

Framing the roof should be 2x12s. The reason is you need the rafter depth at the end where the rafter sits on the outside wall to be high enough off the house plate to get "R" value and a 2" air space "baffels" above that.

Since your home is 75 years old and if its all brick you could use the brick wall and cut rafter pockets in the brick since all double brick walls are considered a bearing wall. Again just giving possibilities here.

I would cut a seat for the rafter to go on new double plate. Also I would use Simpson HZ.5AZ hurricane straps.

Builders Hardware - Building Materials at The Home Depot for the rafter to the top plate on both sides.

Check your codes.

Are you going to have any kind of overhang on the new roof?

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This is excellent information. Many, many thanks.

I've considered the idea of cutting rafter pockets right into the brick, but in the end I think using ledger boards will be easier for me to do, and I believe I'll end up with the same strength, etc. I'd do this for both the floor joists as well as the roof. This should work OK, right? I'd be bolting the ledger board to the brick wall.

So, a couple of quick questions. First, for the upper level of the addition, are the ceiling joists and the roof joists the same? Or do I install ceiling joists and then install a separate set of roof joists above that?

As for the roof construction, I am still confused (sorry!). I am attaching a photo that might help. You see the cutback in the house, right? That's where the addition will be. So, the right wall will be the brick wall, where I will install the ledger boards, and the back wall will be the brick wall. The right wall will actually be built on top of the basement to the left (which is actually a party wall on my property (the city and the neighbor have agreed). What I am just not understanding is how to handle the roof joists where they rest on the stick framed wall on the left. What do you mean by "cut a seat" for the rafter to go on?

Thanks! Sorry I am just not able to picture it!

Quote:

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Or do I install ceiling joists and then install a separate set of roof joists above that?

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It a matter of looking at a flat ceiling inside or a slanted ceiling. Either or can work.

18. Laying Off Common Rafter Seat Cut And End Cut

Measuring, Marking & Layout: A ... - Google Book Search

This should help you. The seat is cut in the rafter and makes a bird mouth.

So far I don't see any pictures ? Check your post.

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Here is the pic, sorry!

Good image. I assume you are going to slant the roof from the back of the alcove towards the front coming towards me.

You have what is called a parapet wall in the alcove that protects the rain from coming down on the steps. Use the brick for a ledger/nailer to attach adjustable rafter hangers. When you or whoever puts the rubber roof on use a side drip edge that has a standing seam. This will act as a parapet wall and control the water from running over the side edge dumping rain on the neighbors

A standing seam drip edge is what's used for a built up roof or a tar roof. Its like a regular drip edge but it a has a little 90 dergee at its edge that is flat if its standard drip edge.

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I'll definitely hire a pro to do the roof. Can't imagine a 10'x5' roof is going to be all that expensive and it pays to have it done right. That said, thanks so much for the heads up on the standing seam drip edge... I will be sure to remember that.

Would something like this work as an adjustable hanger? THA/THAC/THAR/L Adjustable Truss Hangers

So, it seems as though you have lots of experience with this stuff. Would you mind if I asked you a couple of additional questions?

1) The addition will be constructed with wood studs, of course, and covered in Hardie Panel (Hardie's vertical siding. My question is, how do I handle the vertical seam between the addition, Hardie panel, and the original home, brick. Clearly I cannot just but the Hardie Panel up to the brick as water could easily enter, but would flashing work in the application?

2) So, a bit of a math question. Is it possible and code friendly to run 3" PVC through 2x12 joists for a distance of 13' while keeping the 1/4" per 1' slope? I guess I will have to go through about 12 joists. Like I said, the joists are 2x12s and span about 16'. They are 16" OC. I have done the math and I think the answer is yes, but would appreciate any insight.

Thanks!

This is the styles of hangers I was referring too.

Simpson Strong-Tie Video Library

Yes use flashing in the corner where the brick and new wall meet.

Where did the 16' joist come from? I thought the add was 10'

I not sure what your insp is there but I wouldn't be running a 3" through 13 feet of joist. Can the joist be turned if these are new joist?

Check with the inspector. He may say no, or make you sister up where the joist are going to be hole sawed for the main sewer line. Can you drop that sewer line in a built corner chase-way? Or run a soffit under the joist?

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Once again, thanks!

Those hangers make sense. Simpson has so many options!

16' joists exist in the current house. The joists for the addition will be just 5' spans. Since they are existing joists, turning them just isn't an option, and frankly, neither is sistering given the space is finished. A soffit would work, for sure, but I was hoping to avoid it. I will check with the inspector to get his opinion. Generally though, you'd advise against it, right?

Ok, so, for flashing between the addition and the current wall. I was planning on caulking the joint well. Some people have suggested I set the finished addition wall back a little from the brick wall, what do you think about that? What sort of flashing would you recommend using? I cannot come up with anything that seems like it would help?

I wouldn't worry about the brick corner for sealing.

When you go to sheet in the side and I assume you are going to use OSB ext sheeting. Just use 100% silicone caulk the edge of first sheet as you butt that against the brick. After the OSB and what ever house wrap you use. Install the corner flashing with the one end bent at a 90 to the with of the siding " hardie plank" this will double seal at the initial façade and the back up is the sheeting is also sealed.

Setting the wall back really doesn't do anything. If water gets to the OSB its going be a problem weather its slipped back behind the old brick return wall or not.

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Thanks so much. Just yesterday I found a great guide by Hardie. Here is an image of what they suggest. If I follow this, I should be fine, right? Or would you suggest anything further?

Also, it is a multistory house and so the instructions indicate I need to run horizontal Z-flashing at each floor division. How to I handle where the horizontal z flashing meets the corner flashing?

Moving even further off topic(!), the house currently has forced air heat and AC. We'd like to have a vent in each of the three floors (just one as each floor is only 50 sq. ft), but the ductwork for the first two floors would have to run through those solid 8" thick brick walls. Any suggestions? Getting the ductwork to the wall isn't an issue, but getting it through is. Any thoughts?

Hi Stubits I never used Hardie siding here in Pa. But what I'm wondering is what is the 1x4/2x4 end for?
The basic here on the warning from hardie say never butt the siding against the brick which I agree 100%, Apparently they don't want the lap siding to get close to and end wall.
I looked up hardie and read it has a 50 year transferable warranty. What's strange there trim board is only 15 years warranty

This proprietary process for fiber cement trim ensures uniform coverage of sealer and primer, providing an excellent surface for paints. HardieTrim boards come with a 15-year transferable limited warranty.
This proprietary process ensures uniform coverage of sealer and primer, providing an excellent surface for paints and also resisting fungus and mildew. HardiePanel vertical siding comes with a 50-year transferable limited warranty.

I would follow hardies specks to the tee to maintain the warranty. The flashing between the floors is a good question. I would guess they want horizontal flashing every 8 acting as a weep moisture system. The siding must be prone to moisture behind it?. and needs to weep out every so often.

As far as the heat/AC. Its dusty to punch through the brick but We commonly due it as all other contractors. Hears the most important issue. Get at least 3 HVAC contractors to look at you system to make sure it can handle the added addition. Heat fairly easy but AC is a heavy air to push and move. Also think of air returns for each floor.
Example a 90 on a heat run is equivalent to the same resistance and push as a 10' straight pipe.

The horizontal flashing I assume comes with the hardie system. If it does then it mimics the lap siding and sheds water and what ever gets past that is still shedded in the counter flashing where brick meets new wall


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So, what do you use for siding up in PA? Do you have a favorite?

I think the trim is mostly decorative from what I've read and not really required.

The horizontal flashing makes sense to me, but do you have any thoughts on how to handle where it intersects with the vertical corner flashing?

The good and the bad news is that my HVAC system is WAY oversized. We bought the house about 6 months ago and the previous owners had installed a 5 ton air handler in our 1,400 sq. ft. home. We have more than enough capacity to add a couple of extra vents. I'll be sure to add return air vents in all but the bathrooms.

So, aside from all the dust, no worries cutting through the brick, structural I mean? Do I need to add lintels? Or just cut open a hole?

Thanks!

Hears the simple science when cutting through a brick or block wall and what needs supported directly above that cut out.

Weather its block or brick, you look at the opening you want and the top center of that opening. From each side follow the masonry joints heading towards the center of the opening like going up steps following the bed and head joints. When you reach the center of the opening you want, look at the wall size below you (a triangle( that wall area is what will need supported by a header/angle iron/flat steal.

This basic structural science applies perfectly until these variables change. There needs to be enough lateral side weight and volume where you start the steps to support the arch itself. Also if the opening is big and you get to the top and didn't reach the center of the stepped arch, then the load above that will be direct down pressure to your opening below.
I maybe got to deep on cutting openings in masonry, One job alone for me were 28 windows cut in a 4 story all brick ware house for reg windows. Been cutting through masonry structures for 30+ years. Being a mason as my first trade makes it easy for me.

It goes back to the natural arch support. Except your arch is in brick courses that are stepped.


On a small opening like duct work many times there are no lintel's put in for header support. Some times we will just put in some flat steel and grove out the side brick joints and that just carries the brick above.

The duct work you need for those small rooms will more than likely be 6" round or less. If flex duct are used then a metal "thimble" is used to to sleeve through wall.. They also may use 2 1/4 x12 wall stack to punch through and boot the end for grill.

I have no real favorite siding except brick or shadow rock. My town was founded in the 1700s and is all brick in the city. The newer houses have vinyl/ fake stone/ brick or stone. Stucco also


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Thanks so much. I am going to be doing as much of this myself as possible, so it is good to know my options. Which would you suggest, round duct or the wall stack?

Actually both can be applied. When you run a heat run with round pipe and then need to go up through a floor you use a "boot" that goes from round to 2 1/4x12 which can connect to a wall stack or a floor register can connect there.

A wall stack is commonly used when AC is involved. It fits between a 2x4 studded wall. The stack is in that wall cavity and two openings are cut into it for l closeable grills.

In the winter you shut the top grill and open the bottom so heat comes out the bottom. For A.C. you do the opposite. The AC comes out of the top grill (bottom closed) " wall stack" hi lo is the best way to control/distribute the warm and cold.

To many times I'm in a home and the top floor has a floor register which is fine for heat. But for AC it's a bust. The cold air lays on the floor, goes under the door bottom and drops down the steps. That's a perfect way to screw up AC.

Many times the air return is in the common floor hall and that helps suck out the low lying cold air right out of the bedrooms and down the steps

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Ok, so lots here.

First, I am not actually using the Hardie Plank siding, instead, the vertical Hardie Panel. The horizontal flashing isn't part of the system, just standard z-flashing. I guess my question is, when I get to where the horizontal (z-flashing) and the vertical (corner flashing) meet, how do I handle it? Do I run the z-flashing right on top of the corner flashing? Under? Do they butt up against one another?

On the HVAC, our system isn't too advanced. It isn't easy running HVAC in a 75 year old rowhouse with solid brick party walls. On the main floor of the house all the supply vents are on the floor. In the basement and the second level of the home they are on the ceiling. In the addition we are going to keep 2 of the 4 walls as exposed brick. It gives us a little extra clearance and we like the look a lot. Also, with the exception of the new upper level bath, the addition rooms will be connected to currently heated/air conditioned space without doors. I figure we'll maintain the current setup, vents in the floor on the main level and in the ceilings on the other two.

One question I have for the OP

Since this is obviously a row home and this is the back door entrance for both homes... Have you asked your adjoining neighbor if they have any objections to this "addition" you intend on doing? I'd ask before starting the project.

Twinkie-

Thanks again for your concern, but your questions and comments have little to do with the questions being asked.

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Back to the original question. I am going to have a pro do the actual roofing work, I will just frame it. How do I go about building the parapet on the left side?

Also, you're a mason, right? I am thinking about building the lower level of the addition out of 6" CUMs with a brick veneer. As you can see from the photo posted earlier, Id need to build out the wall on the left by about 2.5' and then the front wall is about 5', but it will have a standard size exterior door. The wall would be about 10' high. Should I hire a mason to do this, or is this something I can do myself? Also, we will be cutting a couple of different holes into the house, two doorways on the upper level and we will be cutting out the brick under the window on the second level. Is it possible to reuse this brick as part of the veneer? Also, is it possible to work the veneer into the original brick work to avoid a vertical line?

Quote:

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parapet/ I am thinking about building the lower level of the addition out of 6" CUMs with a brick veneer.

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Yes, I'm a Prof mason along with all other trades form ground up,includes excavating.
I'm not sure how you are framing up that side of the structure. Are you using anchor bolts through the existing brick wall to carry the floor load? Or are you framing up on that side beside the existing brick wall?

The reason I ask is this could make some difference on the parapet wall.

To raise parapet wall remove cap flashing and really check that brick for being sound and tight. More so than not there may be semi loose brick on what's there. If sound lay more brick on to of the existing wall to raise it. Re flash cap.
I don't know what kind of roof you have there now but if you are going to put new rubber roof on addition I would consider doing the rest of the roof in rubber. I could walk you through that also

From what you want to do in masonry work I would strongly suggest to sub that out. There's on thing about masonry work that most don't understand. Is a trade skill that's is developed over years of training and doing it. Its really not a DIY for most all. Its not like measuring and cutting 2bys/framing and roofing.

To reuse the brick as part of the veneer would be bad. You are not going to match the brick there now perfectly. I would reuse the brick for the parapet wall and Recycle that way.

To tie in "tooth" the new brick to the old brick would be good. But not every course. For one it's a lot of work for every other course. Also the new brick need to be dead on in size to match course and mortar Joints. If you want to brake up the long vertical joint tie in one brick every 6 to 7 courses. Or tie in every 3 courses and the tie in will be 3 courses of the new brick then 3 of old brick left alone then 3 new brick tie in. That pattern is along the lines of a "coin corner" look and seems like it was planned for the look. ( which it was)

If you are going to build the lower level out of brick you will need 10" block for foundation and then 6" block.

If I was going to brick veneer the wall I would lay a 6" solid for the wall/floor plate. Frame up from there in 2x6s. use the 4" ledge left beside the 4"x6" solid cap for the brick veneer. I would brick veneer all the way up to roof. If you use 6" block for the first floor to that ceiling and plate from there you will need to offset the second floor wall plate to flush with the first floor brick wall that lays 4 1/2" from 6" block. Also to insulate the first floor with it being block will not be nearly as good as a framed wall. Also there's outlets to consider/ drywall to deal with and block wall etc.


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Thanks so much for all of the help! I really hope you don't mind me picking your many years of experience. I have a lot of questions, so please let me know if I get overwhelming. You have such a great command of the situation. By the way, my name is Adam, what is yours?

Roof

I think I am still a little lost here. Can we go back to the beginning on the roof construction?

I am planning on bolting a ledger board to the 10' brick wall on the left to carry the floor joists. They will span just 5' and rest on the stick framed wall on the other side. As we'd like a flat ceiling in the upper level room of the addition, I am planning on framing the ceiling out the same way, using a ledger board, etc. Now, how do I create the roof? Do you suggest that I run the roof joists perpendicular to the floor joists? That is to say, install a ledger board on the 5' brick wall at the back and span the roof joists 10' to rest on the stick frame wall of the addition? This would be done using the hangers you showed me earlier, is this right?

Ok, assuming that is correct, now, how does the parapet work? I am thinking that we would only really need to build one new parapet, right? Just on the left side to prevent water from running off onto my neighbor's porch, right? The water will run off the front and there are already parapets on the back and right sides, no? Would it be possible to have the roofer just run the rubber roof/membrane up the right and back sides and up and under the roof caps? Does this make sense? Does the parapet have to be built from brick? Wouldn't it be easier, under these circumstances to build it from lumber? Is that not an option? Am I just not understanding something?

Footer/Foundation

The addition will require an L-shaped footer. We have to build out the left wall by about 2.5' and then of course add a footer for the wall closest to the camera (in the earlier picture). Here is DC, footers need to be poured at 36" underground.
1) How deep is the footer usually?
2)How wide would you recommend it be?
3) Do I just build up from the footer using cement blocks? If so, what type and what size?
4) How do I attach the blocks to the footer, just use mortar?
5) Do I need to tie the new footer into the footer of the existing home?

First Floor Construction

I agree with you totally. I would prefer to build the first floor out of lumber, as opposed to CMU's. I am much more comfortable using lumber. My understanding of the code here is that there needs to be 6" of masonry (either cement stem wall) or CMUs before you can use lumber. Does this make sense?

We really do want to do brick veneer just on the lower level. I am actually planning on building the addition out of 2x4s. The space is just so small that every inch counts. We will be using high density foam insulation to get the appropriate R-value.

1) Do I build up from the footer with CMU's until I am 6" above grade?
2) Can I do brick veneer over a 2x4 wall?
3) Do I construct the wall the same? (That is to say, 2x4 framing, covered with plywood or OSB sheathing and then a housewrap of sorts?) Then the mason can come in and veneer the wall, right?
4) We really only want to veneer the first level with brick and then do the other two levels in hardie panel. Are you saying we are going to have some trouble doing that? Will the hardie panel end up being set back from the brick? Is that your concern? **I definitely think I will have a mason do the actual brick veneer, it doesn't seem worth it for me to do it myself and get it to look right.
5) Why do you suggest not using the brick we will remove from other parts of the house for the veneer? If we only veneer the bottom level I think we'll have more than enough salvaged from cutting opening openings in the rest of the home. I would think that brick would match much better than anything else. Are you saying no?

I am sure I have a million more questions, but this is all really starting to make sense. Thanks so much!

See if I can walk you through this. My Geo is footer needs to be 3' below grade.
Dig the footer per your code. Make it 2' wide by 8" thick with two lateral/parallel 1/2 rebar in it. Hammer drill into existing masonry two holes, spaced holes 12"" apart from each other and that 12" center is centered with the 2' wide footer.

So bar is now 4" above dirt of footer and 8" wide. Cut some shorties rebar and use them to stake up the two lateral footer rebar. ( wire tie vertical pin to lateral footer bars to keep them centered on footer crete pour.

I would pour footer no less than 3,500 Psi.

Lay 10" block on footer and stop it rich below finish grade. Now here is where you need to decide on brick veneer or not.

Lay a 4"x6"x16" solid on inside of new block wall. That leaves 4" in front of new cap for brick veneer. This crucial point depending on grade will change to 6" reg hollow and then cap(s)

Are you planning for the first floor to be concrete floor or wood?

Use mortar to lay block ( can tell the mix ratio there too) You don't necessarily have to go to old footer level. As long as your down deep enough by code. Get back to me on first floor elevation on weather it conc floor or wood. I suspect concrete because of no way to really ventilate it. When I say first floor I'm talking dirt grade level. So get back on that.

I'm going to stop there for now. Laying out the block and footer will depend on adjustment of first level floor for veneer and anchor bolter. Perlite (block insulation may play a role here.

Now to the roof.
I am planning on bolting a ledger board to the 10' brick wall on the left to carry the floor joists. They will span just 5' and rest on the stick framed wall on the other side. Good so far.

I am planning on framing the ceiling out the same way, using a ledger board, etc. Now, how do I create the roof? Do you suggest that I run the roof joists perpendicular to the floor joists? Since the roof long ways is only 10 feet+ I would run the top ceiling they way my roof joist will be. Reasons are this will eliminate a 10' ledger board on left side of wall. Also the ceiling joist can assist you to sister nail sloped roof rafters in height and location. This can sit better on the 5'+ outside plate of last front wall. Now here is a decision to make on roof heights which no matter what effects last ceiling height.

The back 5' parapet wall needs to be high enough for slope from there to finish wall plate ( front of addition) Also the side parapet walls may need to be addressed on your side and neighbors. Make sure the roofer runs up the side parapet walls far enough with the membrane. IF aesthetics are not an issue the membrane can run up flush to parapet top and then meta cap on top of parapet.

install a ledger board on the 5' brick wall at the back and span the roof joists 10' to rest on the stick frame wall of the addition? This would be done using the hangers you showed me earlier, is this right? Yes

Get back on the other question to guide you through the foundation/first floor part.

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Ok, the footer is starting to make sense to me. We will definitely be doing brick veneer on the 1st level, no questions there, the wife is demanding it. And the floor of the first level will be concrete slab. As you can see from the photo, there is already concrete there, we would like to pour more to bring the floor of the addition up to the same level as the current basement slab. From what I understand about local code, the stick framing needs to sit on at least 6" of masonry(cement block or a stem wall) above grade.

Just to recap, I will dig a hole 36"+8" deep (per local code) and 24" wide. I will hammer drill two holes into the current footer, 12" apart and in the center of the new footer. I will then add and tie in some vertical bar. Pour the concrete (3,500 PSI), making sure it is 8" thick and that it is nice and level. From there, I will build right up to grade using 10" (solid or hollow???) blocks. Is that right? Now, what do I do here? Again, I want brick veneer on a 2x4 wall. The 2x4 wall needs to be built on top of a masonry foundation at least 6" above grade. What size block do I use? How far up do you suggest I go? Also, once the foundation has been built, can I then pour an addition 2-3" of concrete to raise the slab floor up?


So, you'd recommend running the ceiling joists front to back, instead of side to side like the rest of the floor joists? Is that correct? In that case though, won't I end up with two ledger boards on the 5' wall, one right under the other? Is that OK structurally? I plan on doing this such that the new roof is at roughly the same elevation as the existing roof. In that case the existing parapets for the current roof should be fine. Yes, I will have the roofer run the roofing material up the side of the parapet and under the cap. That just leaves a new parapet on my neighbor's side. How do I actually frame/build that parapet? Structurally, is it part of the roof or part of the wall below? Can it be built out of lumber or only out of brick?

Thanks

When you dig the footer 24" wide by ? depth . 10" hollow block will be laid on the footer.

Some math needs to be done here to set the footer depth so after the 10" block is laid it works out for correct height to start the brick ledge. This may require burying some brick below grade. Also the 6" solid cap needs to work out for the top of that to be flush with finish concrete floor. When done the 1/2 inch anchor bolts will be stick out from the middle of the 6:" solid caps. This is where you will bolt the first plate down. Use plate insulation on 6" solid before first plate to keep out air.

Sill Plate Insulation | Carter Lumber
I'm going to stick on the foundation for now.
There are two ways to set up the conc floor in relation to plate and brick veneer. The base is 10" hollow block. On top of the you need a 4" brick ledge. ( Who ever lays that part out what for a screw up here. Standard brick needs 4 1/4 to 4 1/2" distance from a sheeted wall to lay the brick. The 1'2" if the basic 4" is for the Manson's finger room. On a reg house its not a worry. For you meeting an existing wall is critical to flush new brick veneer to existing veneer.

Back to the slab. 10" block with 4x6w solid cap laid on top of 10" hollow block flush to inside of block wall. That should be your wood plate bolt down. Use plate insulation against the inside of the 6" cap for a thermal brake to concrete floor. To ties the new concrete floor in drill 3/8" holes into the 6" solid cap ( after it sets up good ) Drill about 2 1/2" into the solid 2" down from the top. 3/8" or left over 1/2" rebar should be cut about 16" long which 2"+ goes in the block and 14" is hanging into the new concrete floor. This does two things. It pins the new crete to block and the 14"+ left over solves the problem if there is post settling after backfill on inside of block wall. Inside under crete should be 4" of "2b clean" crushed limestone to level up the inside for prep of new floor. The stone needs to be 4" down from the solid cap. Before you backfill the 10" wall parge the outside thats below grade. Let dry. Apply tar foundation coating over dry parge/Smooth stucco.

On the inside on the wall get 2" urethane foam board ( comes in 2'x8') Get the below grade foam board. Apply that on the inside of the wall starting flush from the stone down. Use liquid Nail.construction adhesive to glue it to the block then back fill. Below the 6" solid cap and flush to the rough in stone prep, Use some more 2" foam board about a 1' wide on all weather exposed perimeters. This is the best way to keep the cold from coming up through the conc slab. So the foam board is and sideways L shape. One part of the L is against the 10" block wall and the other is under new 4" conc slab. Remember to use over all of this a 6 mill plastic before pouring crete. I will stop here to see if you get this so far and then we can move on

This is great info. I want to make sure I have the footing/foundation correct, OK?

In order,

1)Footer - 24" W x 8" H
2)10" block - Right up to grade
3)6" Solid cap with bolts
4)Sill Plate Insulation
4)Sill Plate

OK, now some questions...

1) Is the above outline correct?
2) The wall is going to be built out of 2x4s, not 2x6s. Does that change the size of the blocks?
3) I can't seem to find a picture of a 6" solid cap. What are the dimensions?
4) Does the 6" solid cap allow me to get the required 6" foundation wall above grade?
5) How do I get the bolts into the 6" solid cap block?

I am breaking this up into 2 posts so I don't get confused.

With regard to the slab. If you look back at the picture I posted, you'll notice there is already a concrete slab in the location of the addition. I believe it is 4" thick. I am not planning on getting rid of that (unless you tell me so. I just want to pour an addition 3" of concrete on top of that to bring it up to the level of the current basement floor.

Footer - 24" W x 8" H... YES

2)10" block - Right up to grade .....YES

3)6" Solid cap with bolts... Yes

4)Sill Plate Insulation... After last block is laid solid plate block is laid.

4)Sill Plate... Second on liquid nails in the side of the

OK, now some questions...

2) The wall is going to be built out of 2x4s, not 2x6s. Does that change the size of the blocks?. No not the 10 which I'm sure the code would require since its 3 stories. I would use 10s no matter what. Personally I would stick to 2x6 (R) 19 insulation. What are the reasons for 2x4s? Which may not meet code (3 stories) Either way the second floor joist will be offset to be flush where you are stopping the brick. Or the brick there needs a row-lock course to terminate the diff jumping back to siding if stud wall from basement line up to next floor.



3) I can't seem to find a picture of a 6" solid cap. What are the dimensions? .......15 7/8" long 5 7/8"wide 3 7/8 high" In my area there is a notch in the block 3 7/8 side for anchor bolts to come up through from block below it. ( witch they never work out half of the time to line up)


4) Does the 6" solid cap allow me to get the required 6" foundation wall above grade?. You lay 6" hollow reg block on top of the 10" regs to adjust height(s) then the 6" solid cap block.


5) How do I get the bolts into the 6" solid cap block?. Bolts go past the 6" block as if they aren't there. I lay the 6" block so my anchor bolts are against the side of the solid and use the vertical mortar joints to get past the solid. You will need to cut the 6" cap in half to get the 1' less from corner.

Code for here is within 1' or less of a corner and every 6' to center. In your case of 5" would be 3 bolts in front and two on the short return. Also 1/2" anchor bolts come in many diff sizes check local codes for lengths down onto block wish in you case bare min would be 2 1/4" showing above 6" solid. The add 4" for the cap thickness. At least 6" into the block below the 6" cap. So 14"+ for anchor bolts.

Just saw the pic now in edit. The pic is good except the 6" block/or capp is laid on inside for brick sill out side. I thought upi neede 6" above grade for sill plate. If so then the last course of the 10" block needs to chang back to a 6" reg hollow. You end up burying some brick but thast grade. If you don't want to bury brick then lay a "soap" block on the 4" ledge.


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OK, I am switching this up now a bit... sorry!

What are your thoughts on a slab foundation in this application?

That's more or less what is laid out here to begin with. 10" block to 6" block + cap. 2x6 frame inside on cap. The only diff is lay block 4" below finish floor height. Form up for floor, Pour 4" crete and set anchor bolts in fresh crete. This is 'Slab" foundation. You can still lay the brick and plate on slab. Just to let you know theres not horizontal thermal break in floor. To do that lay a " soap" concrete block for the form. That block is 3 7/8" wide and high and 15 7/8" long. This will be the brick ledge. Apply 4" sill plate insul on side of that block for thermal break.

Adjust conc floor inside for a step up from outside grade. That covers for code of snow etc, OSB sheeted on new 2x6 wood wall. Brick veneer in front of that one story. Wall thickness changes for second floor. Here's where you could make the 5' façade flush to brick wall.

First floor brick wall exactly flush in height to double 2x6 top plate of first floor. Run the 2x12 floor joist the long way (10') and set on double plate but at the same time move them out a couple of inches over brick wall and flush to brick wall. Now second floor studs are flush to brick façade. Add the OSB over second floor studs and hang OSB to slip down over brick wall façade an 2"+. This protects that area from weather. hang Hardie a tad below OSB.

To do this layout, I would move back my foundation wall a couple of inches from the 5' part back. The new brick will be set back from the old a couple of inches. This way when you add the OSB and the Hardie siding for finish facade it will be set back from the existing brick veneer an 1" or so. This protects the side of the siding where it meets the old structure and it can be 90 degree angled flashed where OSB meets the old brick wall and makes a good water shed. You can tie the brick to old every 6 courses and the inside corner mortar joint is not as noticeable which helps break up the 8' vertical straight line.

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This sounds great and makes sense. That said, the only concern I have is that we are intending to leave that cement slab patio off the door on the second level. It is structurally solid and would be an absolute bear to remove. That kind of forces us to run a ledger board on the 10' wall and run the joists over the 5' span, no? That said, can't I still accomplish the same thing? Can the rim joist rest on the brick veneer? Or it is not structural at all?

Basically it is structural. You need to check with code and see if they require a structural OK letter from an engineer. The double/triple joist (5') could be pocket into the brick wall on one side and the other side load is carried over the brick/wall return which an interior double wall plate can carry that.

Old house such as yours usually use the inside brick are used for bearing of floor joist. The old brick have joist pockets. My city is very old and that's the common practice back then. So to prove a point the brick are structural period.

So triple up up short joist sandwich ply to get the 5 1'2 " width, pocket in one side ( existing brick wall. beam over to opposite wall over new double plate cantilever that to flush on the brick return.

Remember I'm a builder not a structural engineer. But I have been around a long time especially in what you are doing there. I'm sure the city needs prints. Always go to them and pick there brain as to whats is allowed by code. Hopefully they won't play the " game"

You need to have a rough drawing possibly. I usually take in my rough Auto Cad drawing in or quick hand drawning in on small jobs. If they require a full blown drawing then at least you have a heads up for architect and drawings revisions are to a min and saves you time and money on revised cost

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I am planning to use bolted ledger boards as opposed to cutting pockets in the brick. I think it will be easier for me to do.

Why is it necessary to double or triple the joists?

I only mentioned cutting pocket in the brick for the last joist at the end 5' wall that's facing the back yard

If you come back in on the brick wall a couple of inches for the above mentioned. Now you have room on that old wall for a beam/joist pocket to help carry the load for the last 5' joist to help bring it out flush to the new brick veneer. Build a beam out of the floor joist to go over and flush to the new brick 4 1/2" veneer. Added joist together and sandwich 3/4 ply or all framing joist to be wide enough to be a nailer for the ceiling below drywall (which you will need one). This will act as a beam to carry the second floor wall and its bearing on one side is 4" into a brick pocket of old and the other bearing side will rest on the return double wall plate from below. This will essentially carry the next two stories floor/wall loads.


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Hmm, I am not getting this at all. I am so sorry!

Im trying to draw and cut and paste to help out here so hang tight.

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Thanks! Looking forward to it.

Hi Stubits. Sorry for the delay.

I could build your addition blindfolded but you think I could figure out this lap top to transfer a drawing from word to this site.

Now I know why I have office people and my simple Auto Cad.

Anyhow think of the second floor 5' out side joist doubled up many times to make a load bearing beam. Now take that one end and pocket that into the old existing brick 4". The other end can run over the top of the 1st floor wood plate and flush to the outside newly laid brick wall on that corner. This will carry the next 2 floors load and give you the flushness you need to the 2 outside walls of new brick



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