Drying and re-insulating a 2.5 year old damp cavity wall

[joe90]

4 hours ago, SteamyTea said:

What is to stop water from getting under the tiles when they adhesive/grout fails,

Adhesive or grout is never used on tiles.

4 hours ago, SteamyTea said:

and what is to stop water building up and over flowing the top of the flashing when the drain fails?

This parapet is sloped so water will run away. not the same as a horizontal parapet.

 

 

[SteamyTea]

15 minutes ago, joe90 said:

This parapet is sloped so water will run away. not the same as a horizontal parapet.

Right, that will help.

 

15 minutes ago, joe90 said:

Adhesive or grout is never used on tiles.

How are they held in place and what stops weeds, or echiums, taking rook between them.

[joe90]

6 minutes ago, SteamyTea said:

Right, that will help.

 

How are they held in place and what stops weeds, or echiums, taking rook between them.

These are roof tiles held on battens not bathroom/kitchen tiles 

[SteamyTea]

42 minutes ago, joe90 said:

roof tiles held on battens

OK

I think I get it now.

GRP is the only answer then.

 

(It would not be hard to mould some GRP into sheets that have battens already in them.  Then just a case of counter battening and slapping on the times.

Fire risk should not be a problem as there are good resins these days, and you would get water tightness and strength built in)

[Adsibob]

After a fairly dry January, with no leaks for most of the month, I saw that it is forecast to rain almost an inch of water on Thursday, followed by an almost as wet Friday. Could procrastinate any longer, so got onto the roof of my rear extension, temporarily removed a strip of seedum (which I imagine will need to come out to install the copings in due course) and clamped on the DPC:

let’s hope this stops the leaks (which only occur after heavy and persistent rainfall) otherwise I’m pretty clueless on how the water is getting in.

[Mr Punter]

You may want to consider aluminium copings for this.

[joe90]

Can you take a photo of the wall with a little of that plastic removed so we can see what’s underneath it?

[SteamyTea]

I have a 'Nigel in the Arches' feeling.

(The 'pips' are 100 years old at 9PM today)

 

[Adsibob]

1 hour ago, Mr Punter said:

You may want to consider aluminium copings for this.

Yes, going to do that in due course, but I can’t get those installed for a while and this will at least confirm that the problem is indeed the top of the parapet wall.

[Adsibob]

1 hour ago, joe90 said:

Can you take a photo of the wall with a little of that plastic removed so we can see what’s underneath it?

If you look back at the previous page, there is a photo, but here it is again:

[joe90]

Sorry, missed that, difficult to see from that, but does the waterproofing under the sedum extend up the wall to be under the new capping?

[Adsibob]

9 minutes ago, joe90 said:

Sorry, missed that, difficult to see from that, but does the waterproofing under the sedum extend up the wall to be under the new capping?

Yes, except that it only goes across the capping by two thirds. Here’s a photo which my architect took at the time they were building, but never showed me until recently when I did an “audit” of this f@ck up:

you can see the roofing membrane goes up the parapet but only two thirds across the brick. A third of the brick is therefore exposed. 
 

on top of that, plastic tiles were laid, but these didn’t overlap each other, leaving grout joints  which eventually cracked (see previous picture) and also they didn’t extend across the whole brick, leaving the edge of the brick exposed. then on top of that layer of tiles, another layer of roofing membrane went on, but again this didn’t go across the whole tile, just two thirds of it (see previous picture). Really odd that each trade (the tiles were laid by one trade, the roofing membrane by another) didn’t think about this at all, and my architect who was meant to oversee this just photographed the mess, but didn’t think to raise it.

 

Edited February 5, 2024 by Adsibob

[SteamyTea]

Having followed this a bit, but not really understood it, I think I am now getting to see the problem.

 

Does the wall face the prevailing wind?

Causing rain to get blown under the membrane.

[joe90]

22 minutes ago, Adsibob said:

you can see the roofing membrane goes up the parapet but only two thirds across the brick. A third of the brick is therefore exposed. 

Great, that confirms my suspicion, you are right, bad design and short membrane which I believe can be cured with proper capping. Not a good design by your architect !!!!

Edited February 5, 2024 by joe90

[Adsibob]

1 hour ago, SteamyTea said:

Does the wall face the prevailing wind?

Yes, as it happens.

 That obviously compounds the problem, but the main issue is that there is almost a third of brick the entire length of the parapet wall which is very exposed even from rain falling perfectly straight in no wind.

[Adsibob]

Ffs. Wind has blown part of the tarp/dpc off. Didn’t want to fix the clamps on too hard, for fear of damaging the membrane. Ffs.

@Pocster please post something funny to make me laugh.

Edited February 6, 2024 by Adsibob

[joe90]

1 minute ago, Adsibob said:

Didn’t want to fix the clamps on too hard, for fear of damaging the membrane. Ffs.

Scraps of ply to spread the load 🤷‍♂️

[Adsibob]

13 minutes ago, joe90 said:

Scraps of ply to spread the load 🤷‍♂️

That’s a very good idea

[SteamyTea]

7 hours ago, Adsibob said:

please post something funny to make me laugh.

It will be raining again soon.

 

[Pocster]

9 hours ago, Adsibob said:

Ffs. Wind has blown part of the tarp/dpc off. Didn’t want to fix the clamps on too hard, for fear of damaging the membrane. Ffs.

@Pocster please post something funny to make me laugh.