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KingsX · Jun 4, 2010, 08:34 PM

I have a friend that is building a modest cottage. And he's allowed to just build on grade on cement pads. But he and I were curious, if you can build a crawl space? What I mean by that is, imagine you have your floor structure for your crawl space built on the pads. And then you basically build a 4 foot pony wall all around, and down the center. And then on that structure, you build your main living floor and so on. In this crawl space would be mainly for pipes, electrical etc, and a composting toilet system (central type). For the time being it would only be 3 season, so heating the crawl space isn't necessary (he'll winterize before winter). But could (if this is even possible) heat that crawl space and use it in winter. I'm assuming this is possible? What do you think? Thanks!

21boat · Jun 4, 2010, 08:55 PM

Is a Home owners association rule or is it a code rule?

Is there a 1 story limit. It would be good to know WHY its pad only..

Crawl spaces has pluses and minus. Normally by code all crawl spaces must be cross vented. On that note the insul properly done is extremely important.

Do you have enough grade area to work with to place a Slab house?

If not then you will need a wall system to bring to flat grade of structure. Bingo crawl space

If you do slab get back for the best way to insulate the concrete floor.

KingsX · Jun 4, 2010, 09:00 PM

No specific rules, other than excavation has to be minimal because it is protected area. But, that being said, he could drive piles etc, but he's looking on inexpensive. Sometimes, they won't allow on pads on grade. But in this case they do. The land is quite level, so minimal adjustments will be needed to level each pad. Keep in mind, there will be anchor blocks that the cottage sits on, they won't just be on pads. The crawl space will be cross vented. He doesn't want to do a slab on grade. It's a post and beam type.

21boat · Jun 4, 2010, 09:49 PM

Obviously the codes will dictate this but sometimes it depends on design to tweak and stay within code.

When you have Pylons or what you call pads those start below freeze level. Now we have a fixed locations. To Span those points one could us a concrete lintel set low but if frost lifts ground, ground lifts lintels You mention knee wall. Well a footing is for that.

I think the best way to approach this is a flexible skirting between pads that can be on grade and yet move without structurally effecting the building.

KingsX · Jun 4, 2010, 09:51 PM

I think I see what your saying. But specifically a built up crawl space under living space shouldn't be an issue.

manhattan42 · Jun 5, 2010, 07:03 AM

Where do you live and under what building code does your jurisdiction operate?

Since you are in a cold climate, this building will need permanent footings placed below the local frost level... even if it is built slab on grade.

If the crawlspace will be heated, it must have its walls insulated to code minimums, usually R-10 if the walls are below grade and at least R-19 to R-21 if above grade.

21boat · Jun 5, 2010, 07:27 PM

Originally Posted by KingsX

I think I see what your saying. But specifically a built up crawl space under living space shouldn't be an issue.

Lets change the wording to think the other direction. Lose "Built up crawl space" and think build down from pylon lintels. Obviously those pylons weather there wood or concrete as you refer to "pads" the house will sit on for a better word Stilts that start below Freeze Line. Just because you have short pylons above grade there stilts non the less. Non unlike a house at the shore for surf to pass under the structure. Now we have that in the brain, think of building down from theses stilts.

I've been changing the word Frost to Freeze simply because a deep freeze is the killer of footers not deep enough. Frost can be in a fall day but freeze is dead of winter.

ballengerb1 · Jun 5, 2010, 07:39 PM

Manhatten asked this already but we are waiting for an answer, where is this located? HOA can their their own codes but you are still required to meet county and state codes.

21boat · Jun 5, 2010, 08:04 PM

Hi bal, Manhattan,
Op post 3# states it's a "protected" area. I assuming its Gov land and they may be the HOA. Which would explin the "pads" and low impact to land
I bet Govs specks are very different then we are used too and usually supersedes the standard building codes. Or has conflicts with each other.

Not unlike historical codes with county codes.. But to clarify it better would be intresting

KingsX · Jun 8, 2010, 11:52 AM

Sorry for not being on here in a bit. I'm in Canada, so frost depth is fairly substantial, I'd say at least 5 feet. Which originally lent me to believe I'd have to either pour piles or drive piles to below frost depth. But code for the area, actual provincial building code (not HOA) will allow just plain old concrete pads, right on grade for cottages. Homes are different. I only suggested protected area, because I was trying to assume why they allow plain concrete pads above the frost line for cottages and not for homes. Either way, built on pads, or piles driven below the frost line, could the idea of a wooden crawl space be okay (treated wood of course)?

21boat · Jun 8, 2010, 02:58 PM

Originally Posted by KingsX

Sorry for not being on here in a bit. I'm in Canada, so frost depth is fairly substantial, I'd say at least 5 feet. Which originally lent me to believe I'd have to either pour piles or drive piles to below frost depth. But code for the area, actual provincial building code (not HOA) will allow just plain old concrete pads, right on grade for cottages. Homes are different. I only suggested protected area, because I was trying to assume why they allow plain concrete pads above the frost line for cottages and not for homes. Either way, built on pads, or piles driven below the frost line, could the idea of a wooden crawl space be okay (treated wood of course)?

Interesting allow a floating pad(s). I guess the theory is as long as the pad doesn't crack when heaving in freeze the house sits on it equally or a tad out of plumb. Bottom line here is if a whole Pad is used and is sufficient without pylons then a small wall would work as long as the pad doesn't crack heave and break smashing the Knee wall/skirting into the bottom of the house.

That's odd in building codes there that a Home is not a cottage yet both are structural and be lived in full time. If I remember correct Canada is very big on moving and taking there homes with them. Explains the Cottage and Home pads verses full footer systems

KingsX · Jun 9, 2010, 09:13 AM

I don't agree that Canada is big on moving their houses. That just seems ridiculous, except for extreme circumstances. I would have thought that would be more likely for Americans because so many of you don't have basements, whereas in Canada a basement is almost required every time. And just being on slab would make it easy for Americans. But anyway, I hear what your saying about the differences between cottages and houses. Of course a cottage is essentially a house. The only reason I can think of why you can do this with a cottage and not a house is because the cottage area might be protected. And there are codes for the size of the pads, you just can't use patio blocks. That's the only explanation I can come up with. As for houses, typically we drive piles, or pour piles and place our footings on them, which are the footings for the basement. And the basement is built up from there. So even the footing are already 8-9 feet deep, with the piles even further down. So I don't know anyone that would move a house up here.

21boat · Jun 9, 2010, 05:33 PM

Originally Posted by KingsX

I don't agree that Canada is big on moving their houses. That just seems ridiculous, except for extreme circumstances. I would have thought that would be more likely for Americans because so many of you don't have basements, whereas in Canada a basement is almost required every time. And just being on slab would make it easy for Americans. But anyway, I hear what your saying about the differences between cottages and houses. Of course a cottage is essentially a house. The only reason I can think of why you can do this with a cottage and not a house is because the cottage area might be protected. And there are codes for the size of the pads, you just can't use patio blocks. That's the only explanation I can come up with. As for houses, typically we drive piles, or pour piles and place our footings on them, which are the footings for the basement. And the basement is built up from there. So even the footing are already 8-9 feet deep, with the piles even further down. So I don't know anyone that would move a house up here.

I saw a program many years ago where they showed Northern Canada moving house. As far as basements in my state I say 95% of the houses has basements. That's part of what I do build Basements. About your footing system one seems to wonder the cost. They way I read this is piles are in 8 feet under ground and what, Above the grade starts the basement? If so we don't call it a basement it's a first floor. Or, is the basement partially in the ground between the piles and how does that get filled in?

KingsX · Jun 11, 2010, 12:21 PM

Yes, actually in the far far north, houses tend to be movable. But that's because the ground is what is called permafrost. Which means that it is essentially a frozen bog. And they have to take very special care when building on it, because if the heat from the house melts this soil, the house will sink. But barely anyone lives up there anyway :)

I was just thinking no basements in the states, particularly where it doesn't freeze. But anyway, what I meant was, often but not always, depending on soil, a basement is excavated. Lets just say, 6 feet down. At the bottom of that they would either pour piles or drive piles. Then rest the basement footings (house footings) on that. Then build the basement. Then the house on top. Then back fill the basement, so that approximately 2 feet is out of the ground etc. Basement windows tend to be above grade but not always.

It does cost more, but keep in mind that this isn't what happens all the time. Usually building engineers will do soil test. If the soil contains a lot of a particular type of clay, it can absorb the water and heave the basement floor and foundation etc.

21boat · Jun 11, 2010, 02:21 PM

Kingsx , Thanks for getting back on that. Being in the trades its always very interesting on how different Geo's dictate different of construction. I work and build in the states as well as Puerto Rico and its very different in the Caribbean..

KingsX · Jun 11, 2010, 08:32 PM

I can imagine. I spoke with my brother, who is currently build a house. And the town he's building in, there is no code for piles. Basically all you have to do is excavate the basement, and either use concrete footings, or a poured continuous footings. But the builder he used still poured piles because they didn't know what the soil was like there (as opposed to where they normally build which is about 30 miles away or so). They could have done a soil test, but didn't (probably wouldn't have needed piles) but it was built into the price, so he got them anyway. Bizarre.

EDIT: take a look at the wiki article on permafrost, I actually didn't know that much about it. They say that if you drive wooden piles 15 meters down, the temperature doesn't change there and the building is stable. 15 meters! That's crazy, that's like 50 feet or so.

http://en.wikipedia.org/wiki/Permafrost

fastmax4 · Jun 24, 2011, 10:00 AM

Hello people,

I'm in the process of building a cottage on concrete pads myself. The floor joist span is going to be 12.6 feet made from 2x10 fir. The floor area will be two of the 12.6 foot span being a 26 foot wide building outside measurements. Pads will be on both outside walls and down the center. There will be three laminated beams, one on each outside wall and one down the center. What size of concrete pad is required? 24"x24"x6" is a code minimum. Will this do for this size of building (26' wide by 28' long)?

Thanks
RG

twinkiedooter · Jun 29, 2011, 05:57 PM

Originally Posted by fastmax4

Hello people,

I'm in the process of building a cottage on concrete pads myself. The floor joist span is going to be 12.6 feet made from 2x10 fir. The floor area will be two of the 12.6 foot span being a 26 foot wide building outside measurements. Pads will be on both outside walls and down the center. There will be three laminated beams, one on each outside wall and one down the center. What size of concrete pad is required? 24"x24"x6" is a code minimum. Will this do for this size of building (26' wide by 28' long)?

Thanks
RG

You need to think more like this being a manufactured home placement type of thing. The beams down the middle or whatever need to be properly supported on individual pilings every so many feet.. The pilings must be placed upon cement columns drilled and poured into the ground.

A professional ground driller must be used to reach the proper depth or the house will sink. Also keep in mind do you want to put concrete block around the perimeter for support of the entire house? In manufactured double wide homes this is what they do. They first do the concrete block crawl space and then place the home ontop of the outside and inside supports. They way you are thinking of doing this your home is sure to sink, get lopsided, unlevel in a short amount of time. You have no idea how easy it is for a heavy structure like a home is to sink into the ground.