Solid Stone Exposed Gable End Penetrating Damp

[Mictheslik]

Hi everyone,

Long time lurker, first time poster. I've been picking up lots of useful information from this site over the last couple of years so thought I'd better register (and selfishly ask a question that's making me tear my hair out!)

I've been trying to get my head around where the rain is getting in to my gable end wall. We sit on an exposed ridge-line in the Mendips, so frequently get blown horizontal rain. When we moved in the gable end looked like this and we were getting a lot of damp in the bathroom around the windows, especially after heavy rain.



I hacked away some of the plasterboard around the reveals and found a void with sodden insulation in it. Removed it all and observed for a few months. In heavy rain with a SW wind (wall is SW facing) water would drip down the face of the lintel and onto the tiled surface below. I tried to put together a drawing at the time for my builder.



The sills of the loft window needed replacing, which I suspected could have been letting some water in. The pointing also wasn't in great condition (the front was pointed in cement and starting to cause the usual issues). Got the builder in to replace the damaged sills and repoint the gable end and front in NHL 3.5. Work was completed in October. They also skimmed back over the hole in the bathroom (with Gypsum).



Fast forward 4 months and the wall is definitely drier, and dries out more quickly. However, on three occasions (which is less than before!), we have had the same damp spots coming into the bathroom. Always during torrential SW driven rain.



I initially thought it might be the wall getting saturated, but as part of a wider bathroom renovation, I've stripped the other window (which I have discovered has gypsum skimmed over paint, over more gypsum and some kind of cement underneath!).



Whilst one corner has been getting a little damp, the other is completely dry, so I can't think that the wall itself is saturated as surely it would cause wider damp issues? Any ideas for a next step would be great appreciated. I'll finish with a few photos taken this morning of the exterior. We had 41mm of rain last night and extensive damp in the usual spots. The worst area for ingress is the top right of the open window as viewed from outside.







Any ideas gratefully received!

Thanks!
.mic

 

[aockenden]

Hey we have very similar window construction in our Welsh stone cottage (3 lintels, outter is stone, middle and internal both wood). And we also had a very similar leaking situation when south wind-blown torrential rain would cause one of the downstairs windows to leak with water running down the inside face of the external stone lintel and land onto the sill surface below. Ours was bad enough we needed to put plastic tubs on a couple occasions to catch it.

We finally resolved the issue by replacing the poorly installed window that sits directly above the leak. The fact that the worst damp penetration you are getting on any window is coming from the top corner of the window with the loft window right above it is suspicious. Have you physically gotten up on a ladder and looked at the condition of the loft window? The slope on the external sill for that window is correct? Is there a drip-channel on the underside? How’s the render or mastic that seals the gap between the window frame and the stone of the reveal? Is there any gap between the bottom of the frame and the sill’s top surface? Is that sealed properly with mortar or mastic? Can we get closeup pics of the window installation from the outside of this loft window?

Here’s a pic of our own exposed lintels on the leaky reveal just to prove I’m not making stuff up:

 

[Mictheslik]

Thanks for the reply: Glad (if that's the right word!) we're not the only ones in this situation.

The loft window looked to be in pretty good condition when I went up on the scaffold in October. One of the main reasons for having the work done was to replace the badly spalled original sill on the loft window which was done by the builders. They also redid all the mastic where the pointing or new stonework needed sealing, and I redid any remaining original mastic (not as tidy, but made sure that it was sealed!) Don;t have a long enough ladder to hand (need to borrow from a neighbour, but got a few old photos and some leaning out from the window below....

Sill before the work:


Sill after the work. Slope appears to be draining in rain, and the groove underneath promotes dripping away from the wall.



Bad photo from inside the loft showing my very messy sealant!



.mic

 

[aockenden]

And how’s the condition of the red brick section near the pinnacle of the gable? Pointing there sound? What about the roof above? Any potential leaks / broken tiles that might be allowing rain to come through and down into the top of the stone wall?

 

[Mictheslik]

Brick pointing looks OK, but I've only just noticed the end of the ridge tiles looks a little suspect:



Sent this photo over to my roofer for his opinion...

.mic

 

[Mictheslik]

Update after another day of torrential rain….now got similar leaks around ground floor window and door….joy!

 

[aockenden]

Sry to hear that, this weather has been especially unforgiving for old stone houses.

It could all be coming from the same leak if it’s high enough up and just percolating down through the stone until it hits a lintel.

 

[Stevers]

Q. Where have all the cowboys gone.
A. To fit placcie fascias and barge boards to nice old houses.