Originally Posted by
contrebasse
I'm having a new garage built. The reinforced footings are in clay, but are HUGE (600x600) given its just supporting a single garage. theres a slab on top of the footings
600x600 is not huge by any means, but it sounds about normal ( I have gone down 1200mm in clay for foundations) .
Clay is the most reactive ground you can have as it shrinks when dry and expands when wet.
However, the wall brickwork is now complete, and now all its dried out, I can see that the mortar had shrunk away from the bricks in places, so in effect there's a crack. this also joins up with other cracks in a zigzag patter over a couple of courses.
Small hairline cracks can be expected as the sand dries out, it is caused by the clay in the sand drying out, a lot of sand has too much clay in it for my liking.
Zig zag cracks make me think there is another problem, like settlement.
I mentioned this to the builder and he said yeah that's normal, all brickwork does that. But I've never seen new mortar cracking like that. Feels to me like the bricky didn't put enough of the sticky stuff in his mud ...
Test the hardness of the mortar after a few days with a nail, if the mortar scratches really easy then there isnt enough cement in it.
If the nail just scratches the mortar then it is fine.
Inside, the engaged piers were built up to ceiling height and tied in with standard brick ties every few courses. But now i notice that there's a crack running down the back of each pier. Builder says its because the pier was built onto the slab, whereas the wall was built onto a course of bricks resting on the footing.
Correct, you cant build one part of the brickwork on a slab and one part on footings without different movements between the two.
The movement will show up as a crack, but, seeing as how the piers are engaged I dont see too much of a problem apart from the cracked mortar.
Is this normal? If not, should I ask the builder to fix it? What is he says "thats just normal".:~