Concrete slab against garage wall?

[6ply]

There is a concrete path running around my garage and at some stage in the past someone filled in a section with a very weak concrete or mortar mix that inevitably has broken up. This has been removed and I am now ready to fill in with some proper concrete.

I'm wondering whether it would be good practice to pour the concrete up against the wall or whether I should have a thin strip of ply shuttering or even DPC separating the slab from the garage wall. What do you think? Incidentally the wall is not damp I just sprayed the hose earlier.

 

[Morris]

Where's the dpc? You should be an amount below that. 4"?

 

[Pigeon_Droppings2]

I'm wondering whether it would be good practice to pour the concrete up against the wall

Personally I prefer a good gap between the cement and brick work (4-6inches).

 

[Onoff]

The DPC should be 6" above the surrounding concrete path.

Leave a foot gap and fill with chippings as in a French drain.

 

[6ply]

Where's the dpc? You should be an amount below that. 4"?

Yes, should be 2 bricks below, but it isn't. There is however quite an overhang from the eves which gives some extra shelter.

 

[6ply]

The DPC should be 6" above the surrounding concrete path.

Leave a foot gap and fill with chippings as in a French drain.

That's a good idea but I tend to use this area for grinding, etc. (It's just outside the door) and having loose gravel would make sweeping up annoying.

 

[6ply]

I wonder if there's something I could use instead of chippings that would not be loose but could offer some drainage.

 

[gaz1]

id leave it alone

just remember any filled up areas that i filled up with concrete leaves no where for the rain and more so in heavy rain no where to go

 

[6ply]

id leave it alone

just remember any filled up areas that i filled up with concrete leaves no where for the rain and more so in heavy rain no where to go

Surface water won't hang around here. It will either go down the drain, into a nearby gravel area or straight down a steeply sloping drive.

 

[6ply]

Anyway getting back to my original question would it be good general practice to fill the concrete up to and against the brick wall or should something be placed between the slab and the wall?

 

[colnerov]

I had a similar scenario with the patio ending up half a brick above the garage base. I just lathered it with Bituminous paint up to the top of the brick, and then paved it. No water in the garage but half the run is under a generous overhang of the roof and is not subject to prevailing wind and rain. YMMV.

 

[Agrismith]

Anyway getting back to my original question would it be good general practice to fill the concrete up to and against the brick wall or should something be placed between the slab and the wall?

Small chance of expansion problems. You can buy thick hard bour or foam to against the wall to allow expansion but the seeming lack of it to the side of your hole without problems probably says a lot.
I would however suggest Dowling into the existing 3 side to avoid movement.

 

[cocker]

Flexcell , I think is the stuff to use . It's a bit like compressed cardboard , about 1/2" thick . There's something else , new plasticy foam stuff . Don't know what that's called .
For a little bit like that , I'd put 3 or 4 bits of cardboard (to make up 1/2" ) full depth and all the way along .

 

[6ply]

Small chance of expansion problems. You can buy thick hard bour or foam to against the wall to allow expansion but the seeming lack of it to the side of your hole without problems probably says a lot.
I would however suggest Dowling into the existing 3 side to avoid movement.

You are right about expansion, I think it would be limited. I hadn't considered dowelling.

I used some softwood when I built a ramp around the side.

 

[brightspark]

You are right about expansion, I think it would be limited. I hadn't considered dowelling.

I used some softwood when I built a ramp around the side.

View attachment 501250

when it gets wet it will rot and keep the wall damp shot a bit of visqueen up against it and a bit of a fall on concrete away from the wall if its above dpc

 

[MetalMonkey]

I'd probably stick a piece of DPC in there, fold it to make a bit of an upstand that comes just slightly past the top of the slab.

 

[tom2207]

I wonder if there's something I could use instead of chippings that would not be loose but could offer some drainage.

no fines concrete ..

 

[6ply]

when it gets wet it will rot and keep the wall damp shot a bit of visqueen up against it and a bit of a fall on concrete away from the wall if its above dpc

I'd probably stick a piece of DPC in there, fold it to make a bit of an upstand that comes just slightly past the top of the slab.

I could do that. I've got some thick visqueen.

 

[tom2207]

make sure the fall is away from the wall , if not adjust the back level until it is , use a bit of polythene or what ever you have , and pour it ,, I wouldnt imagine it would cause any grief .

 

[Erie Fred]

Anyway getting back to my original question would it be good general practice to fill the concrete up to and against the brick wall or should something be placed between the slab and the wall?

Yes. There is a standard product that looks like tarred Homasote used all the time for this.

Also, on industrial pours, we used a felt product approx 1/2" thick with a "zip strip" on top.
IIRC Sika sells it.

Affix against wall, pour concrete. When cured, remove top zip strip, it leaves a 1/2" deep groove
to apply Sika sealant to seal the joint from water ingress.