Leak Help! Cavity tray? Roof? Help!

[Ollyfp]

Is it worth carrying out an experiment? You could tape/fix a sheet of plastic over the area for a few weeks to see if the problem persists. You've been living with this for 5 years. It must be getting you down a bit. Really hope you get it sorted!

 

[Luke1988]

If you force compressed air in through a weep vent, you should be able to hear it emerging from the other weep vents... if they exist.

Yeah tbh I’ve never seen water coming out of them but it’s also hard to see when you’ve got streaming water coming down anyway

 

[Ollyfp]

Yeah tbh I’ve never seen water coming out of them but it’s also hard to see when you’ve got streaming water coming down anyway

Compressed air might force sitting water out through the vents. Have you got a leaf blower or a wet and dry vac with an output? Worth a try!

 

[Ollyfp]

Have you checked that your window drain holes are clear? There should be at least two that are accessible to clean with a pipe cleaner or a length of electrical cable where the base of the window meets the sill.

 

[freddiemercurystwin]

There should be a tray immediately above the flat roof, if installed correctly they cannot allow rainwater past ergo the tray must be installed incorrectly/missing.

 

[Luke1988]

Have you checked that your window drain holes are clear? There should be at least two that are accessible to clean with a pipe cleaner or a length of electrical cable where the base of the window meets the sill.

Not checked but the last water test wasn’t on the windows and still leaked

 

[wessex101]

How can I check that?

The only way is to look, so a boroscope or remove a brick. If the damp is due to lack of stopends then the damp tends to be concentrated towards the ends of the tray. If the damp is below the middle of the tray then it is unlikely to be due to this.

 

[Luke1988]

There should be a tray immediately above the flat roof, if installed correctly they cannot allow rainwater past ergo the tray must be installed incorrectly/missing.

Well they’ve been “looked at “ twice so would hope they are there

The only way is to look, so a boroscope or remove a brick. If the damp is due to lack of stopends then the damp tends to be concentrated towards the ends of the tray. If the damp is below the middle of the tray then it is unlikely to be due to this.

Yeah it’s hard to tell where the water is coming from. When the garage was leaking we had a hole in the ceiling and water was coming in under the blockwork and out across a beam.

 

[^woody^]

Well they’ve been “looked at “ twice so would hope they are there

Don't be so sure.

I've been to a job where several builders made several attempts to stop this very same issue at first floor level but in a solid 9" wall. One of the attempts was to actually drill and install a chemical damp course like you get at ground level. I posted the photo on here previously. None of the builders had a clue.

I've also seen, more times than I care to remember - cavity trays just placed against the inner leaf, randomly nailed or stuck with silicone, or even just up against the insulation at the back of the external leaf, and going jack.

Back fall of the tray in the cavity, holding water and leaking under laps is also in my top 10, as is cavity trays above or below flashing level.

Trays work, that's a fact. If there is a tray and there is still damp, then the tray is incorrectly installed.

 

[Luke1988]

Don't be so sure.

I've been to a job where several builders made several attempts to stop this very same issue at first floor level but in a solid 9" wall. One of the attempts was to actually drill and install a chemical damp course like you get at ground level. I posted the photo on here previously. None of the builders had a clue.

I've also seen, more times than I care to remember - cavity trays just placed against the inner leaf, randomly nailed or stuck with silicone, or even just up against the insulation at the back of the external leaf, and going jack.

Back fall of the tray in the cavity, holding water and leaking under laps is also in my top 10, as is cavity trays above or below flashing level.

Trays work, that's a fact. If there is a tray and there is still damp, then the tray is incorrectly installed.

Oh trust me there’s no assumptions here based on the issues we’ve had

We’ve had independent people review it with cameras and flagged nothing so will see.

Did a similar test in our garage earlier and definitely looks like brickwork/whatever is behind it