Gable end render

[Lofty145]

Hi all,
I had my gable end rendered a couple of years ago but we got cracks and it hollowed out and we had water penetration.
I hacked it off and had it rendered again just before Christmas and it was mild.
Within a couple of weeks we had water penetration again.
I have tapped all round the render and no hollows.
I believe now that it could have been the window causing the problem by not being masticked?
The water comes in where the 210mm celcon blockwork meets original brickwork.
I have attached photos, any advice would be much appreciated.

 

[clive12345]

Hello
I cannot see the photos ,but you do need mastic .

 

[Lofty145]

Thanks I hope photos are there this time?

 

[Lofty145]

Here

 

[clive12345]

Hello Lofty
It is difficult to see much from your photos.
You need the photos the correct way up.
Is the celcon block wall single skin?Where are the blocks in relation
to the window on the gable-end ?
If you posted some more details somebody else might have some advice.
Looks like you will need a bit more than mastic.
Good luck

 

[Micilin]

I have a horrible feeling that it was rendered without proper prep or mixes.

If it has hollowed out, perhaps the first coat dried before it set and cured due to the suction, and the second coat (if there was one) has only that coat to adhere to.

Probably hard to answer but if you knew the prep, application and mix you would have your answer on my scenario .

Also if it is a single skin as above from Clive, it would be even more vital to have even have insideand out done in sand and cement properly.

 

[Lofty145]

Hi, thank you,
I had the gable re-rendered in December as it was mild because water had been coming through previous cracked render. first coat was put on and second coat the following day. 2 days later it rained an we had all that bad weather and before long water was appearing on the inside in the same places as before at the point where block meets existing brick, below but to the left and right of the gable window.
There are 2 or 3 very small places where the render appears hollow but it seems hollow all along the bottom where it has gone light grey. The rest of the render is patchy and darker.
There has been one suggestion to me that water could be backing up and in behind beading although I am still of the belief that it is window or failed render?
The gable window sits to the front of the block work. On the original cracked render I had some damp appear on the cheeks inside the window.
I had the inside of the blocks done in sand and cement but as you can see, I have taken it off on the inside where I have taken off insulation to allow blocks to breathe and dry out.

Bottom right corner window ext

• Lofty145
• 3 Apr 2014
• 1

Bottom window ext

• Lofty145
• 3 Apr 2014
• 1

Inside right of window

• Lofty145
• 3 Apr 2014
• 1

Bottom right ext showing greyed render

• Lofty145
• 3 Apr 2014
• 1

Ext gable end

• Lofty145
• 1 Apr 2014
• 1

Untitled

• Lofty145
• 3 Apr 2014
• 1

Bottom left of window inside

• Lofty145
• 3 Apr 2014
• 1

Bottom right int

• Lofty145
• 1 Apr 2014
• 1

Damp patches appearing bottom left

• Lofty145
• 1 Apr 2014
• 1

 

[Lofty145]

Hi, I have just cut out more insulation and taken off the render inside.
Then I decided to take off some skim layers below the block work/beading level and uncovered all this damp in picture.
Could it be beading or just water penetrating existing brickwork or just trapped damp that had come down from block work?

Untitled

• Lofty145
• 5 Apr 2014
• 1

 

[Micilin]

Looks like your outside needs sorting out properly, back to basics. From top down where can the water be getting in?

It looks like inside needs all coming off with proper waterproof render to keep salts back, and outside needs loose removing before assessing again.

 

[Lofty145]

Thanks, I am almost at that stage. Just waiting a little longer in the hope someone might come up with direct answer.

 

[Micilin]

Inside has to be redone, but only when you find out the source of ingress and deal with that first.

If everything is eliminated apart from the render itself, then redo outside render.

From pics it looks like all needs sorting.

Trouble with those blocks is that hacking off May damage them if the render is well keyed, but I suspect it isn't.

 

[joe-90]

The first thing you have to ask yourself is why all the other houses in the area, that have no render at all, are not getting wet yet yours is? And why your house was able to stand for decades without render but not getting wet?

It's NOT the faulty render. It may be the windows or maybe the roof where the problem lies.

That render is rubbish, btw, and will soon fall off.

 

[Lofty145]

Thank you,
Just had builder come and look and they seem to think its the beading as it is only 1/2 course below the blocks, has no drip and should be bell cast beading. They have suggested take off the bottom 15-18 inches of render and put a damp proof strip along the line where block meets existing and take the render down another course to finish off with bell cast beading?
Does this make sense?

 

[Micilin]

The first thing you have to ask yourself is why all the other houses in the area, that have no render at all, are not getting wet yet yours is? And why your house was able to stand for decades without render but not getting wet?

It's NOT the faulty render. It may be the windows or maybe the roof where the problem lies.

That render is rubbish, btw, and will soon fall off.

Would celcon blocks be fairfaced ?

 

[Lofty145]

Hi,
Yes they are fairfaced celcons.