Leak from Coping Stones

[wa12dsa]

A few months ago i had my garage converted into additional living space by a specialist conversion firm, as part of the job I paid them for a rubberized roof covering on the existing flat roof.

Before they got started i had a builder round to replace the failed concrete lintel above the garage door with a steel one, he rebuilt the single skin 9 inch parapet wall above the lintel and put the old coping stones back on top.

A few weeks after the garage was done we started to notice drips of water on the inside of the window forming a pool on the window sil.

The conversion firm have sent 3 different staff out to look at it. The first one thought that water running down the wall was getting in at the lintel (which is covered by a pvc fascia) and he put loads of sealant around the PVC. The 2nd thought the problem was the roof he thought water was getting in around the flashing so he sent for the roofer.

The roofer was annoyed and adamant that no water was getting in at the flashings and told the other half that water was geting in through the coping stones and down the cavity and it was the fault of the builder who did that job for not fitting a cavity drip tray. The company then gave me a quote of £1k for taking down the parapet, fitting a drip tray and re doing the bricks.

When i pointed out that the wall was single skin with no cavity at first they said maybe they should put some lead under the copings then they came out and painted some grey sealant type stuff all over the back of the bricks, the top of the coping and along the points where the rubber joins the bricks.

We had hoped that this would work but yesterday when it rained we had pools of water again however they had moved from the middle of the window to the right had side at the lowest point of the parapet.

Please could you have a look at the pictures and let me know what you would tackle first. Chances are i will now get someone else to sort out the problem as i've lost faith in the original firm and they subcontract everything so whatever i get done will have a hefty mark up on it.

The very last photo is looking towards the neighbors side, it is attached to ours and he has no issues with leaks.

https://drive.google.com/file/d/1S89gkhlFsD2iDyAlWM-Hajx7VyMcVZui/view?usp=sharing
https://drive.google.com/file/d/19dMZTdaxzmAqv6NoipxQzhq9iq75cZ-q/view?usp=sharing
https://drive.google.com/file/d/1mrJsth9nyd5Q8bLTZGjXJqCY_qO-e_lw/view?usp=sharing
https://drive.google.com/file/d/1cqZ1ihCmoBaJl_xQ8FpsYmcnSACIIzKN/view?usp=sharing
https://drive.google.com/file/d/1LaridzpxIdV4vuJL5KwV302fXJXLFedE/view?usp=sharing
https://drive.google.com/file/d/1ValW64lkTFSxQhruMof7t0zmXEIsVS2U/view?usp=sharing
https://drive.google.com/file/d/13Z9INXgo06LRpm9aEzyAkfZdZMNXT4Jl/view?usp=sharing
https://drive.google.com/file/d/1wbWNo98EQCfq3KXQR5Z7cjAXN7Oxv8bP/view?usp=sharing
https://drive.google.com/file/d/1CdMTMh_w_yt0SARGy6o34ERK4WSvv1lV/view?usp=sharing

 

[John D v2.0]

The neighbours pointing isterrible so he's doing ok without leaks.
Your coping stones should have more overhang and should have a fall to the rear. My guess is water is running back on the brickwork at the front down the wall and behind whatever that PVC trim is.
The job of the stones is to direct falling water away from the brickwork and if any water that guys them ends up on the wall they haven't done the job.
You could always do a dye test, mix water and food dye or similarsimi spray plenty of each mixture in a different area, then you'll know where it's from.

 

[^woody^]

Looks like it's related to the lintel install or the front brickwork.

You could coat the brickwork with a clear silane based water repellent, but I don't know what's going on behind that ugly plastic cover - that could be where the problem is.

Edit: in fact why is there an ugly plastic cover ( ugly plastic cover made uglier by being in two pieces) when he has installed a steel lintel!

And just because the wall had been rebuilt in solid brickwork does not mean that than integral tray should not be fitted. Has a DPC been fitted under the copings?

 

[wa12dsa]

Thanks for the replies.

The plastic cover is one piece the line on the photo is actually black stain from the rain running down from above.

Underneath it is the steel lintel which isn’t covered by brick so we thought it needed covering as you don’t see many like that where we live. Should we be looking at getting the steel rendered in concrete to make it waterproof?

I don’t know what if anything was put under the copings as before this issue I had thought they were just there to look nice .

If we got new copings with more overhang to prevent water running down the front would there still be issues when the rain naturally blows onto the bricks.

 

[^woody^]

Looking at the other pictures now and the stain position, it is apparent that issues are related to the lintel install and not the roof. The water is from the inside of the wall and exiting at the window head

No DPC under the copings would be an issue, but it looks like a proper steel lintel was not used, rather a steel beam.

The "builder" should have fitted a proper lintel and that would function as a tray to cast water to the outside, and it would have prevented the need for that stupid plastic strip.

 

[wa12dsa]

Thanks woody, I’ve just noticed a diagram of yours on another thread about finishing an rsj with flashing, cement board and brick slips, I might get a builder round to quote on upgrading the copings and finishing / waterproofing the rsj and hope this solves the problem.

When the first builder came to put the steel in it was a tatty garage with an ill fitting door so maybe they didn’t think it was worth keeping the rain out!