Water Leaking into Garage

[jroy_998]

Hi All,

I'm hoping you can offer some advice on an issue I spotted at the weekend.

We've recently moved into a house with a detached garage and when all the rain came down on Saturday I noticed it was coming in to the garage from one of the corners.

After it stopped i had a quick look outside and could see some loose/missing bits of pointing round the edge and on the stairs.

Do you think it's a case of patching up the bits that have come off, or is it worth removing and redoing? What sort of material would you use? Cement, screed? Combo of both? Or is it a case of it needs a bit more than that?

For what it's worth here's the aftermath today, mostly dried, but still on bit which looks quite damp.

Thanks in advance!

 

[Deluks]

Sand and cement to replace that. Try 3 sharp sand, 1 building sand, 1 cement. Mix it stiff, not too wet, smooth it down with a trowel after it's had a few hours to set (or borrow the wife's cake icing spreader!)

I suspect you will still get some ingress even if you do all this. Might be an idea to paint something like Thompsons water seal over the mortar fillet and the wall for a bit of extra protection.

 

[jj4091]

Pre fab garages are terrible for leaking under the walls.If it was mine I would remove it all then pump plenty of silicon sealer in then re-point it all.

 

[Harry Bloomfield]

After it stopped i had a quick look outside and could see some loose/missing bits of pointing round the edge and on the stairs.

If I'm understanding your photos correctly, those steps rise directly alongside the garage, suggesting there is also a high level of soil piled tight against the garage wall. If that description is correct, there are no easy solutions to the ingress.

When I laid the slab to build my own 24x12 pre-fab garage on, I should have made the finished floor level, a little higher than in fact did, because it settled a little way below the general ground level. It was fine during most wet weather, but if there was a lot of rain come down, over a short period, like yours, it would flood. I added a web of cement around the inside, as someone has done in your case. It would work for a while, but always, eventually the expansion and contraction movement between the slabs, would crack the cement. I was even considering at one time, laying more concrete over the entire floor slab. Your web of cement, looks as if it may not have been there long.

I finally solved the ingress, just last year, by digging around the edge of the slab, and adding some kitchen waste pipe at the bottom of the trench, inclined down towards a drain. I drilled numerous 10mm holes in the pipe, all the way along the trench, then added bits of broken concrete, tile, and similar over the entire pipe length, covered over with loose pea gravel. Basically, what is called, a French drain. You can buy ready perforated pipe, made for the job. The pieces of tile, bits of concrete etc. help keep dirt from blocking the holes.

I have had absolutely no ingress since doing the later fix. The idea is, give the water a lower place than the slab, to run to and get away.

 

[noseall]

Hi All,

I'm hoping you can offer some advice on an issue I spotted at the weekend.

We've recently moved into a house with a detached garage and when all the rain came down on Saturday I noticed it was coming in to the garage from one of the corners.

View attachment 393468View attachment 393469View attachment 393470

After it stopped i had a quick look outside and could see some loose/missing bits of pointing round the edge and on the stairs.

View attachment 393471View attachment 393472View attachment 393473
Do you think it's a case of patching up the bits that have come off, or is it worth removing and redoing? What sort of material would you use? Cement, screed? Combo of both? Or is it a case of it needs a bit more than that?

For what it's worth here's the aftermath today, mostly dried, but still on bit which looks quite damp.
View attachment 393475

Thanks in advance!

Am I seeing several feet of soil piled against a pre-fab sectional garage?

 

[jroy_998]

Thanks All,

Hopefully this gives a better view of the structure.

How big a problem would the soil piled against it be? Obviously the water ingress will be an issue, but will it cause any other issues?

To be honest, we're wanting to convert this into something a bit more permanent/potentially use it within a wider extension in the next few years, which I imagine at which point we can look at the soil around it. We just want to get a few years of semi-decent use out of it before then.

 

[jroy_998]

Sand and cement to replace that. Try 3 sharp sand, 1 building sand, 1 cement. Mix it stiff, not too wet, smooth it down with a trowel after it's had a few hours to set (or borrow the wife's cake icing spreader!)

I suspect you will still get some ingress even if you do all this. Might be an idea to paint something like Thompsons water seal over the mortar fillet and the wall for a bit of extra protection.

Thanks @Deluks, I might try this at the weekend as a first attempt. When you say I replace I assume you mean take everything existing out and put new mix in rather than patch? I'll do this around the top and steps, leave it to dry, then coat this and the wall with Thompson's. Is there anything else you'd recommend whilst I'm on with it?

 

[Harry Bloomfield]

How big a problem would the soil piled against it be? Obviously the water ingress will be an issue, but will it cause any other issues?

That is pretty much the layout I had assumed. I don't think, with all that soil piled up, there will be much you can do, from the inside. I'm surprised the water ingress isn't very much greater. My best guess is that whoever built that, put in extreme effort to seal the garage, on the outside, where it needs to be, to prevent ingress.

Your only way to improve it, would be to somehow remove the earth around the walls, and leave a gap.

 

[accelerator]

Where you have your fork and spade, is that the back left corner of the garage?

Does water pool on the paving stones behind the garage?

Initially I would waterproof that big hole you have on the corner at the top of the stairs, i.e. probably a mortar repair, then see what happens.

You will then probably need to seal the gap between the all the steps and the garage as water is probably getting in from here too.

You need to think what will make the best waterproofing. I'm not an expert here, but you can initially use mortar, but then think about another compound you could use over the edges of the mortar to better seal it, e.g. some sort of outdoor silicone.

 

[Deluks]

Thanks @Deluks, I might try this at the weekend as a first attempt. When you say I replace I assume you mean take everything existing out and put new mix in rather than patch? I'll do this around the top and steps, leave it to dry, then coat this and the wall with Thompson's. Is there anything else you'd recommend whilst I'm on with it?

No you can just patch it into the gaps.
But having seen the wider picture, I'm not sure it will make a lot of difference, particularly as you have a weep hole in the retaining wall right behind that corner.

What's the fall on the steps? If any of them angle towards the garage then that's just channeling rainwater into the building.

It's hard to properly diagnose as we can't see what's under the steps. If they put some membrane up against the garage wall and used plenty of free draining rubble underneath, then you might have a slim chance. But as nosy says, if it's soil against a prefab, it becomes a bigger job to sort out.

I think you've got to choose between the lesser of two evils, dig out the steps and make a gap with a drainage channel at the bottom, or tank the garage internally.
I'd opt for the latter.

 

[cdbe]

As above, replace the fillet inside and outside and add to the steps. Use cement SBR slurry as a tanking/bonding agent and as a waterproofer in your mortar mix. You need to be thorough and methodical in your preparation and work and be aware that SBR only has a short working time.

The fact that water only seems to be entering via the wall/floor join suggests that the prefab concrete is doing a better than expected job at resisting water - hopefully they put visqueen against the walls before they backfilled.

 

[Harry Bloomfield]

The fact that water only seems to be entering via the wall/floor join suggests that the prefab concrete is doing a better than expected job at resisting water - hopefully they put visqueen against the walls before they backfilled.

and/or, silicon sealed the joints between the panels, plus panels and floor slab.

 

[jroy_998]

As above, replace the fillet inside and outside and add to the steps. Use cement SBR slurry as a tanking/bonding agent and as a waterproofer in your mortar mix. You need to be thorough and methodical in your preparation and work and be aware that SBR only has a short working time.

The fact that water only seems to be entering via the wall/floor join suggests that the prefab concrete is doing a better than expected job at resisting water - hopefully they put visqueen against the walls before they backfilled.

Thanks @cdbe. Really appreciate it. So it would be a case of adding some SBR to the mortar mix suggested above and using that to replace what's there/adding to steps? Or is there a different ratio you'd recommend?

Do you still reckon it's worth adding something afterwards too for additional waterproofing?

Also Is there any particular SBR you'd recommend and what ratio would you suggest?

Appreciate this will all potentially be a sticking plaster, but if I can make it semi usable for a couple of years whilst we figure out what to do with it, I'd be happy.

Cheers.

 

[jroy_998]

No you can just patch it into the gaps.
But having seen the wider picture, I'm not sure it will make a lot of difference, particularly as you have a weep hole in the retaining wall right behind that corner.

What's the fall on the steps? If any of them angle towards the garage then that's just channeling rainwater into the building.

It's hard to properly diagnose as we can't see what's under the steps. If they put some membrane up against the garage wall and used plenty of free draining rubble underneath, then you might have a slim chance. But as nosy says, if it's soil against a prefab, it becomes a bigger job to sort out.

I think you've got to choose between the lesser of two evils, dig out the steps and make a gap with a drainage channel at the bottom, or tank the garage internally.
I'd opt for the latter.

The steps are pretty much even/angling away from the garage. The step at the top does angle down though. I'd have to check next time it rains, but i imagine water would sit at the corner a bit.

It looks like someone has tried to sort this before as I can see some fraying silicone type substance on the joint.

Interestingly, now it's properly dried, I'm only seeing a couple of damp patches left, one in the back left corner and one at the bottom of one of the side walls. I'm not sure if this indicates a weak point where it's coming in, or just a point where it takes longer to dry?

 

[Harry Bloomfield]

I'm not sure if this indicates a weak point where it's coming in, or just a point where it takes longer to dry?

It could be either. You would need to see which gets wet first, when it rains, to determine where it is coming in.

What I will say is - you have remarkably little ingress, considering how high that soil is piled up behind it. Whatever measures they have taken to keep it out, are working exceedingly well!