water leaking through new opening in cavity wall?

[Smath22]

6 months ago we converted the garage into a utility and study, we had two steel rsj installed, to create an opening in the cavity wall. All inspected and signed off by B\C

This evening we noticed water dripping in through the plaster which covers the rsj and cavity, never happened before.

The garage had a new warm deck flat roof, made of a single ply mechanically fixed membrane.

My guess is water is getting into the cavity in the wall and leaking down onto the new plaster, my question is where would this come from ?

The roof, the new flat roof or somewhere else? There is a window in the cavity on the first floor, but not above the where the leak is happening ?

 

[Alastairreid]

Sounds like you need cavity trays.

 

[Smath22]

I did read about them after a quick google search, but they seem geared towards condensation, this appears to be to much water, it must be getting in somewhere, I know bricked absorb water but really that much?

Worth noting we have had heavy rain on many occasions since the work but this has never happened.

 

[freddiemercurystwin]

Despite the myth, brickwork as an outer skin is not waterproof.

Cavity trays are most certainly not geared to reducing condensation. They keep any water out that may get through the outer skin. This wasn't one of nosey's jobs was it?

 

[Alastairreid]

When the rain drives against the wall is when you will get problems.

 

[s60tsy]

check the top of the window and the sealant, the mother in law had a problem with driving rain running down a gable wall and coming in at the top of the frame onto the reveal. tube of silicone sorted it!

 

[Smath22]

Had the roof people out, fully check all the flashing and seems all is water tight, however the state of the mortar on the end wall is in a state of disrepair, there is a lot of damp crumbling mortar, lots missing, and generally in a bad state.

Is it fair to state that because of this the driving rain would have had no problem getting water into the cavity, it was suggested the wall need repointing?

I know its hard to say with out seeing but does this sounds reasonable ?

 

[Alastairreid]

Perefectly reasonable!

Get it pointed and take it from there.

 

[s60tsy]

does the window have a top piece that sticks out further than the frame?

 

[Smath22]

does the window have a top piece that sticks out further than the frame?

Don't think so, not a 100% what you mean though.

Needless to say, today's weather has brought more water coming through.

 

[s60tsy]

the frame may have an add on piece that sticks out further than the frame and lintel, sometimes letting water backtrack into the reveal

 

[Smath22]

No there is nothing sticking above window.

Builder actually came out Boxing Day and re cemented some of the ridge tiles and filled holes in the pointing as the weather forecast was bad.

This has made no difference.

Looking in the loft is all dry.

He is convinced because of the type of brick used in the construction of the house it is just absorbing too much water which is running down in the cavity. He says I should apply thompson water seal. he thinks this will cure the problem.

I don't know enough about bricks etc. can they really absorb enough water for it to drip down and create a large pool on the floor?

Long term we are going to have cavity trays fitted but that to me doesn't address the problem? We have not had this before, although weather has been particularly bad.

 

[catlad]

This has probably been happening for years and the water just ran down to your foundations, but now you have interrupted that with your new opening it a problem, that was one of the reasons why cavity walls were invented and then cavity trays.

 

[Smath22]

This has probably been happening for years and the water just ran down to your foundations, but now you have interrupted that with your new opening it a problem, that was one of the reasons why cavity walls were invented and then cavity trays.

While I have no doubt that water is penetrating the outer skin, this has never shown before and we have had the new opening for over 6 months now, i'm concerned as to why now and not before?

I have removed the internal window cill so I can see into the cavity, and while there is signs of water running down the inside of the outer skin, water is actively dripping from the the cavity insulation?

I took some pics as best I could which I'll post.

I have looked at the roof again and it looks fine, and the loft is completely dry. I did notice if you lift the roof tiles there is no covering over the cavity it is open to see in.

As always any advice is greatly appreciated.

 

[Smath22]

Untitled

• Smath22
• 1 Jan 2014
• 1

pic of cavity, what is doesn't show it the water actively dripping from the cavity insulation.