Render Over painted pebbledash.

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NickHM

New Member
Hi,

Sorry if this has been done to death!! I've read a few threads on this but they are a bit technical!
I'm not a plasterer myself, but researching the best options for covering over 1940's pebble dashed house. Any advice would be appreciated. The job will be done by a professional once we have decided the correct approach.

The dash is firmly attached to the house, so knocking off seems like a big job, we've tried chiseling off a patch and its solid. Hoping a cover option would work.

We'd really like to end up with the monocouche finish.

I'm looking at a few options and have questions on each if that's ok..

1. ONE COAT DASH COVER – EWI-065 (OCDC) – 25KG. I can see this needs Fibreglass Mesh embedded within it and can have a silicone render afterwards. Can the silicone render be done with a monocouche finish or just a smooth finish? Can silicone render be in a permanent colour or do we have to paint?

2. Can we just prime and then K rend a scratch coat with a fibreglass mesh embedded then have the monocouche finish as a second coat. I'm reading that K rend is breathable, so would this work?

3. EWI store recommended a Solid Wall Insulation system, but were not particularly helpful on the phone about cost compared to option one or two. They said only 20mm thick boards are available, but that leaves issues with window reveals etc. Can you get a 10mm thickness board as we're not bothered about it for insulation purpose just to level the pebbledash out beneath. Is this system far more costly?

Just after opinions on which way to go if anyone can help. Option 2 is the most attractive for simplicity and finish, but not sure it's viable? Option one would be next choice if it can have the monocouche finish. But obviously don't want it coming down in 2 years because we've used the wrong materials.

Thanks for your help.

Cheers
Nick
 
You will need at least 40mm insulation to be of any benefit and as to window sills and eaves etc there are retrofit trims available to accommodate. An ewi installer will have examples of work or photos he can show you. There are some youtube vids if you search, Sto do a few.

As to going over the old painted render with solid render that is possible with Parex and Fassa products. Parex make a base coat call Parinter and Fassa make K Over. The existing will need to be fully cleaned of dirt etc first. You can then base, monocouche or render and silicone. As for costs for the insulation I would be looking at £100m2 plus scaffolding. The other around £65-75m2. Measured through openings.
 
Tha
You will need at least 40mm insulation to be of any benefit and as to window sills and eaves etc there are retrofit trims available to accommodate. An ewi installer will have examples of work or photos he can show you. There are some youtube vids if you search, Sto do a few.

As to going over the old painted render with solid render that is possible with Parex and Fassa products. Parex make a base coat call Parinter and Fassa make K Over. The existing will need to be fully cleaned of dirt etc first. You can then base, monocouche or render and silicone. As for costs for the insulation I would be looking at £100m2 plus scaffolding. The other around £65-75m2. Measured through openings.
Thanks for your reply. The insulation option is just to get a base to work from rather than for the insulating property of the board and really my least preferred option. (Cost!) EWI Store where suggesting it was the only real option, but not overly helpful on the phone, which is how I ended up here. (Thanks for replying!) Good to know we could use a solid render option. Thanks for the info on the base coat I'll look into the Parinter and Fassa make K Over options. Not being in the trade I was struggling to find anything other than the ONE COAT DASH COVER that info is really helpful. Thanks for the guide on cost, it's probably confirmed that i need to look more at the solid render. As i'm not looking for the benefit of the insulation then paying a 1/3 more seems pointless. Cheers Nick
 
Very funny year build would be depending in you have a cavity you may need a lime render houses in this period is when the change from old to new took place you need to be careful in what you use and do a bit of investigation work first
 
Very funny year build would be depending in you have a cavity you may need a lime render houses in this period is when the change from old to new took place you need to be careful in what you use and do a bit of investigation work first
Thanks for that. It has a cavity. The main bit we're rendering was built in about 1948 we believe, it was an extension built around a smaller older farm house (1800's). As we're changing doorways windows etc, we can see it's block work with a cavity then brick and pebbledashed. I've not really seen this sort of dash much, not loose stones chips that rub off , but really solid and deeply embedded into the mortar.
IMG_0576 2.JPG
 
If you think you are 100% sure the is a cavity I would hack it all off and k rend it with their more expensive insulated backing coat. I think if you put anything over that crack it would come back
 
If you think you are 100% sure the is a cavity I would hack it all off and k rend it with their more expensive insulated backing coat. I think if you put anything over that crack it would come back
Thanks, appreciate your help. It's not actually a crack in the picture, it's where we ground out to try chipping off. Couldn't make a dent on it is the issue!
 
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