Enlarging concrete slab and frost heaves

[vdotmatrix]

I just poured a cement mix to enlarge a 4x6 slab to 8x4.

The forms i used butt up against our brick home.

Should I fill in this space with concrete

or

Should I fill it in with mortar

Do I have to worry about frost heaves if water get in between slab and house?

by filling this space, which the existing slab had a space of about 3/8" space in some places (probably by accident), would seal up any water or snow getting in there and causing problems.

thanks


vdotmatrix@gmail.com

It's sometimes better to be lucky than smart.

[LazyPup]

It needs to have some means of an expansion joint between the slab and the foundation wall, otherwise as the slab expands from solar heat in summer it would push severe stress against the foundation wall which could result in cracking the foundation wall.

You concern about water getting between the slab and the foundation wall is also a very valid consideration because water expands when it freezes, which would also put stress on the foundation wall.

Given that it is now too late to get an expansion joint strip in the joint, I would elect to fill the void between the slab and the wall with a tar base expansion filler. The expansion filler material will adhere to the concrete maintaining a water tight seal while still remaining pliable enough to allow the slab to change dimenesions without placing strain on the foundation wall.

Contact a local masonary supply center (a place where they actually sell brick and block in bulk) and they should be able to recommend a product, hopefully packaged in caulking tubes for easy installation with a caulking gun.

[vdotmatrix]

quote:Originally posted by LazyPup

It needs to have some means of an expansion joint between the slab and the foundation wall, otherwise as the slab expands from solar heat in summer it would push severe stress against the foundation wall which could result in cracking the foundation wall.

You concern about water getting between the slab and the foundation wall is also a very valid consideration because water expands when it freezes, which would also put stress on the foundation wall.

Given that it is now too late to get an expansion joint strip in the joint, I would elect to fill the void between the slab and the wall with a tar base expansion filler. The expansion filler material will adhere to the concrete maintaining a water tight seal while still remaining pliable enough to allow the slab to change dimenesions without placing strain on the foundation wall.

Contact a local masonary supply center (a place where they actually sell brick and block in bulk) and they should be able to recommend a product, hopefully packaged in caulking tubes for easy installation with a caulking gun.

The main reason I have a concern after 15 or more years that the slab has been there is that NOW, There will be an 8x3 metal shed on it and the roof of this shed angles down towards the house. Anywater or snow that comes of will send water and snow right into that space between the house and the slab. That is why I am worried about frost heaves.....

So I can get my air chisel and chisel out a space and place an expansion joint in there and then continue the concrete from the slab to the house-a distance of about 3 inches that was occupied now by the 1x2 I used as a form for the length of the rear of the slab.

can w ater get into that expansion joint and cause trouble?

It's sometimes better to be lucky than smart.

[handyhecx]

Try some self leveling sealant with backer rod under the sealant. I have used it with great success.

http://www.sikaconstruction.com/ht-c...Sealant-us.pdf