Water penetrating through wallthat I

[iwanttodiy]

hi guys

Just had a new extension shell done and apparently builders says it’s all water tight and have now deemed the project as complete.

Recently had a plasterer come to plaster the walls and we noticed a wet patch in a corner of the wall which the plasterer will not plaster as the plaster will just drop off.

I’ve gone back to the builders who claim that it’s not a leak and it’s not possible for water to breach a cavity, so thus yet he is refusing to believe it’s his problem.

Not sure now what to do, except get rendering organised to waterproof the exterior of the shell. But I don’t think i should patch this problem, as water should not be breaching from the external leaf to the internal leaf anyway.

I would like to get some sort of evidence to suggest poor workman ship from the builders. Does anyone have any suggestions what to look for that I can use as evidence to get the builders to come back and correct the work.

 

[^woody^]

Does anyone have any suggestions what to look for

A hole in the roof

 

[iwanttodiy]

A hole in the roof

Originally thought it was a hole in the roof, but as the water is starting in the middle of the wall, that rules that out?

Attached some photos of the wall and corner. The tissue is not wet by the ceiling, but 3 courses below it?

 

[noseall]

Originally thought it was a hole in the roof, but as the water is starting in the middle of the wall, that rules that out?

Not if it is dripping straight down the cavity and then hitting a tie wire....?

 

[Notch7]

So you had a builder, build a whole extension for you, it has a leak, but its nothing to do with him.

What is the top of the wall / roof junction?

 

[noseall]

it has a leak

Is it deffo a leak? If it suddenly appeared after heavy rain then yes - it's a leak, particularly if it was not there previously.

Is there is a valley directly above the problem area? Post a piccie of the outside please.

 

[iwanttodiy]

I don’t have a picture of the finished roof as of yet. I’ll get it shortly, however it’s a parapet roof, see attached during construction. The leak is in that corner where the squirrel is.

The parapet has been sealed up with a Layer of dpm across the cavity, osb3 boards closing the cavity, and fibreglass lapped from the roof over the top of the osb3 with external grp trims on either side of the wall.

I also investigated outside, and noticed above the exterior brickwork, that the mortar joints were not pointed, seems that they just shoved the block into place and not jointed it. I’ll upload a piccy shortly also. Pretty much found quite a large gap between the blocks where there is no mortar. I think this could be the cause of the leak.

 

[Notch7]

I don’t have a picture of the finished roof as of yet. I’ll get it shortly, however it’s a parapet roof, see attached during construction. The leak is in that corner where the squirrel is.

The parapet has been sealed up with a Layer of dpm across the cavity, osb3 boards closing the cavity, and fibreglass lapped from the roof over the top of the osb3 with external grp trims on either side of the wall.

I also investigated outside, and noticed above the exterior brickwork, that the mortar joints were not pointed, seems that they just shoved the block into place and not jointed it. I’ll upload a piccy shortly also. Pretty much found quite a large gap between the blocks where there is no mortar. I think this could be the cause of the leak.

Parapet walls are prone to leaks.

Although with grp up and over, it should be well sealed on top.

 

[cAtLeYx]

Have you checked the up-stand detail on the roof light, I assume that's what's showing in the last photo>
?

 

[iwanttodiy]

I have a feeling it’s definately not the roof it’s got a 100mm fall across 6 meters and that corner is the highest point falling away from the wall.

Here is a picture of the external leaf. That course of block is just above the ceiling. That gap in the mortar is right above the wet patch on the wall

 

[Leofric]

Open joints and what looks like loose fill cavity insulation and damp patches inside !
Is the blockwork going to be rendered ?
Being below a high point in the roof wouldn't matter if the parapet finish was leaking.

 

[^woody^]

I have a feeling it’s definately not the roof it’s got a 100mm fall across 6 meters and that corner is the highest point falling away from the wall.

Here is a picture of the external leaf. That course of block is just above the ceiling. That gap in the mortar is right above the wet patch on the wall

https://imgflip.com/memegenerator

 

[iwanttodiy]

Is the blockwork going to be rendered ?

Yes, will be getting someone else (not these cowboys) to render in the new year. Trying to get the inside sorted so we can move back in, but plasterer doesn’t want to plaster onto damp walls so trying to get the leak remediate by the builders. Although render is waterproof, the builders should at least make it watertight as a first line of defence before the render goes on.

Showed the picture to them builders, and seems they acknowledge the poor mortar. Still to get a timeline from them to fix it.

 

[wessex101]

I do not think the poor mortar joints to that one block on it's own would be enough to cause the damp patch. There would still have to be a way for the damp to bridge the cavity so as it looks like someone has replaced that block at some time I would be curious what is behind it.

I would also be having a very close look at the parapet detailing above the leak.

 

[iwanttodiy]

I’ll take a look as well as a picture.

Maybe put another layer of grp over the top just in case.

I’ve currently got that corner covered by a tarpaulin to try protect it from moisture in preparation to get plastering done