Porous pebble dash?

deandean

Problem with the OM's house, I'd welcome any suggestions 'cos I am stumped.

The windows were replaced about 10 years ago and the surrounds had to be built up again and new pebble dash applied.

Any time there is driving rain, water gets in over & under the windows, sometimes they have towels out, and the walls feels wet on the inside (solid concrete wall).

After several attempts at sealing around the windows, we reckon water is getting in through the dash. The new dash applied around the windows is, er, porous - it has lots of little holes in it and I reckon the water is getting in right through the dash.

The dash has been painted a couple of times with Weathershield at this stage, no improvement. I've researched the problem and suppliers are suggesting a complete re-finishing of the house exterior at huge cost, however the problem is only with the newer dash around the windows.

Any thoughts as to how I could seal the dash? There's no way I'm going around filling every one of those small holes :eek:

moy83

Well if you are sure its coming in through the patched dash you could put a plaster band around the windows that is a bit wider than the new patch work . Depending how many windows there are it would still be a bit of work for a plasterer but way less than replastering the full outside and should solve the problem

TheLastMohican

Looking at the pics, this looks like painted wetdash rather than pebbledash. With pebbledash, most plasterers would add waterproofing to the buttercoat to stabilise it. This would stop the penetration. However with wetdash, you don't add waterproofer to the scratchcoat as you need porosity to get the dashing to adhere. But this should keep the driving rain out - unless the scratchcoat is very thin/non existent. Could the water be getting in at the joint where the window and wall meet?

deandean

Thanks for the replies. I am looking at a couple of paint-on products...

DublinDIYguy

You could try Santex high build exterior paint. It's very thick, like a cross between paint and plaster. It's good for hiding imperfections on exterior walls, but I'd say you could use it to fill all those small holes.

Blankety

not sure if you got this problem sorted out. I had the same issue a few years back and solved it by painting on a clear sealer. probably wasn't as bad as yours but a sealer may work for you.

southkilkenny

Hi folks,
Similar issue here, no apparent holes but lots of water coming in and appearing around the windows in times of driving rain. What was the clear sealer that you painted on and did it work well or for long? Thanks in advance, Mike.

deandean

Hi Mike, OP here. It's a very old thread but I did get a solution to my problem after about 6 years.
I applied 2 or 3 different products to the dash around the windows. Still water got in when there was driving rain.
Then I thought there was a structural problem with the (Rationel) windows and I was looking at getting them replaced.
Finally a contact thru a friend, a very experienced builder.
He determined that water ingress was due to the way the windows were installed.
There wasn't a good seal between the bottom of the window frame and the wall.
Leaving the window in situ he took out the old sill and put in a new one, and did a proper job. Then the exterior had to be replastered, and the inside wall that was water-damaged was stripped and replastered.
It cost over a grand per window (times nine!!!) but finally there is no water ingress.
Hope this helps.

whizbang

Probably would be cheaper to go complete external insulation

listermint

whizbang wrote: »

Probably would be cheaper to go complete external insulation

It wouldn't be no. Average semi d 12k plus