Gap between slab and wall

[info2x]

Hello all,

Been lurking for a bit now and to get started with the garage that came with my new home. The floor looks like it's made up of 6 slabs with expansion joints in between them. I've noticed on several of the walls a gap has formed allowing me to see the sand underneath. I'd like to seal this up. The gap is probably 1/4" at the widest parts and in some parts tapers to nothing, making backing rod with a sealant on top difficult. What do you guys recommend?

Thanks

 

[hdshinn]

How thick is the slab? Assuming 4" nominal look at some type of pourable sealant perhaps.

 

[info2x]

Thanks for the quick reply.

Slab seems to be about 5" thick at the edge of the slab so unless the sand has migrated up the side meaning I have a thicker slab or they undercut the center I'm going with 5".

Most of the fillers I've found seem to have a max of 1/2" for depth of crack...

 

[hdshinn]

... Most of the fillers I've found seem to have a max of 1/2" for depth of crack...

That's primarily due to the physical stress on a sealant joint that's designed to move quite a bit. I personally wouldn't be too concerned about the depth other than the amount of material it will eat up.

But you could simply sweep some sand into the joint to within 1/2" or so of the surface to take the place of backer rod. Then you could use a gun grade sealant which is a lot less mess than trying to pour the joint full. I'd still mask off the floor and perhaps the wall so you could even tool the joint flush & smooth.

No sign of water migration inside I trust.

 

[ConCretin]

You can buy 1/4" backer rod. When the joint gets too narrow for that, you probably don't need it anyway.

 

[info2x]

That's primarily due to the physical stress on a sealant joint that's designed to move quite a bit. I personally wouldn't be too concerned about the depth other than the amount of material it will eat up.

But you could simply sweep some sand into the joint to within 1/2" or so of the surface to take the place of backer rod. Then you could use a gun grade sealant which is a lot less mess than trying to pour the joint full. I'd still mask off the floor and perhaps the wall so you could even tool the joint flush & smooth.

No sign of water migration inside I trust.

I'd be worried the sand won't move the required amount and I'll end up cracking the slabs. Which upon closer inspection last night appear to be 2 slabs with reliefs cuts to make them look like 6 total slabs.

No moisture issues that I can see.

You can buy 1/4" backer rod. When the joint gets too narrow for that, you probably don't need it anyway.

I didn't see that last time I was that the store, but I guess I'll have to look harder.