I have a stable block wall on a shed (14x20) that is 40yrs old. I live in MN. A foundation expert told me the foundation was done moving and stable and he could patch the various cracks in the exterior block, cover with screen and then mortar the whole wall. That was costly. There are only a few cracks running up and down. No loose mortar. I want to re-build the shed, what can I get away with doing to keep the cracks from growing and the walls stable. It will be a little heated cottage in the woods when completed.

Being in MN and having it heated means winter cold,snow permeating the cracks,heat from the interior melting that snow,it freezes somewhere down the line, at the wall base,in the cracks,etc.

We all know what damages ice can do to nearly anything(see:Ice age)

In the smaller scale of things,the cracks you have now will eventually become much more than cracks.

The idea proposed is a very good idea,but as you see,costly.

I would ask,do the cracks go through the entire walls,outside the block and inside the block.Are the cracks on the mortar lines,or through the actual block?

Back to you.

some of the cracks go all the way through the block but most do not. The foundation is backfilled (has been for 40 yrs) and the floor of the new shed is just even with the top course of block. The new wood floor rests on the old slab floor and is insulated with 3 in. ridgid foam between the treated joists. I have added flashing under the bottom course of lapsiding to keep runoff from the top of the foundation. Can I clean out the cracks and mortar them, and then just trowel on a coat of mortar? Will that stick to the block? Is there another product I can use to seal and clean up the foundation? I wanted to use some red faux brick tiles I have and do a random exposed brick in patches here and there. What do you think?

So this is only the foundation that is block,not all the walls?That's a horse of a different color altogether:)

Sure you can clean out the cracks and fill, that's done all the time(tuck-pointing), that contractor seems to be looking for some extra $$$ to do an over-the-top smear coat.

You'll need to get as much loose material out of the joints, up to a point.. more than a half inch and you'll be into the inner webbing.Kind of hard to fill when there's nothing behind the mortar!

If there are actual blocks split,you might put those faux bricks over those areas.. making sure you seal the edges so water(snow,ice,etc) can't get behind and further damage the openings.

Prep would consist of cleaning out the openings,perhaps hosing out the holes to get rid of any loose sand/dirt... Then use a bonder(Elmers glue makes a concrete bonder)mix with the mortar(if the hole is big enough,I apply it directly on the opening as well,and point.)

You can also use the bonding agent for the faux bricks as a glue base.. mixed with the mortar to set them in,you should have real good adhesion.

If you are going to cover the entire base with mortar,I would consider using not a trowel but smear coating(with gloves,naturally), you have better control of the mixture,a brush in your other hand to rub the mix into any/all openings, and to smooth out the surface.The mix would need to be loose to allow you time for application and overall appearance would be good once dried(don't point with loose mortar and expect it to dry without cracking though,use stiffer pointing and allowing it to dry for a day or 2,then smear coating over entire surface.

I use a curling hand application.sounds mundane but it really does work nicely.You can make designs in the mortar(a stucco effect,a swirl pattern,with the brush you can make many styles and designs), imagination and ingenuity go far playing with wet mortar... HA!:p

Hope this helps,

KBC