Remedial Rendering??

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Joh

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Hello
This is my first posting ... I would be very grateful for your advice :RpS_crying:.

We live in the Peak District and have a stone fronted 60s bungalow with pebble-dashed sides and stone quoins. We have added an extension to the rear - this is in high density block. The condition of the pebble-dash is variable - some is sound but patches have blown - and it all looks very dreary. NB Using hammer and chisel we have removed areas to see what lies beneath - it's brick and seems in reasonable nick!

1.
We're reluctant to cover over the dash (even supposing it proves sound enough for the most part) because there would be problems at the quoins - an extra layer of render would project further out than the stonework and look daft. Yet, I have some reservations about knocking off the dash for fear of internal damage to plasterwork - perhaps this is unfounded??

2.
Monocouche renders like K-rend and the Weber products give a finish that would look good on our property but I have read some negative reports about them - eg brittle/easily damaged; cracking/difficulty in patching; green staining after only a few years on north-facing aspects etc. Do you have experience of these products/know how they behave after several years?

3.Also I am concerned about achieving a seamless junction between the new blockwork and the existing brick wall - different expansion/contraction rates/cracking?

4.
Another concern is that of cracking on an existing wall. In the 1970s we had a long hot spell (hard to believe now!) which resulted in the clay substrate drying/shrinking to the extent that lots of properties around here suffered mild settling. We have a short crack on our gable which extends diagonally from the upper corner of a window to the roof line (about 3 feet long). This is on the side of the house which visitors see when they arrive. If we go for a monocouche finish any such crack would stand out like a sore thumb. It's only a few mm wide and doesn't appear to have altered over the years but I do wonder whether it opens and closes a fraction depending on the weather conditions. How should we deal with this so that the chance of the crack opening up again is reduced to a minimum?

Finally .... if you have any other advice regarding our job which I haven't asked questions about I'd be very pleased to hear it.
 
it sounds like you may be best using a weber insulation system to reduce any risk of cracking you could build out the qouins first then they would still stand proud webers m1 leaves same scratch finish the insulation batts can be mechanicly fixed to exsiting wall and bridgeing new work to old will not be a problem
 
From what i under stand off your post , you want to retain the exist stone quoins and leave the new render sat back a little as is.
You could just remove the loose dash and patch in then top with an adhesive base rend like Parex Mate, Marmorit sm700, fully meshed, and then top with a silicone grade 1.5- 2mm top coat which will give the effect you are looking for , this system would be very flexible, and the full mesh would sort most of your problems including a seamless joint between old and new (depending on the length of the elevation) and any small settlement cracks, any large cracks do need to be addressed though , wether by chemical or mechanical bond.
There are many options and materials available, but from your description this sounds like the best available to you and probably the most cost effective.
An externally insulated system would be ideal though in this situation , if you can bare to loose the stone coins and have maybe some fake ones cast in a modern material to give the same effect. Plus the benefits off insulating your walls would speak for themselves.
Here's a couple of videos that might help shed some light , and i know a few of the other lad's on here have a lot off info and vids regarding various materials
http://www.youtube.com/watch?v=CeT8eWGrz0A
http://www.youtube.com/watch?v=DdbTUQ5zUrg
 
Hello again and thanks for the quick replies ...

warrior .. you've hit the nail regarding the quoins. We would like to keep the existing ones .. those on the extension are set to conventional render thickness (don't want to mess with these) and at the front of the house we'd need to remove the stone down each side and replace with larger pieces .. would be quite a task. Although extra insulation is attractive, we have effective cavity wall insulation and the new-build part is well padded!

A question warrior - what would be the total thickness of the solution you suggest - ie meshed base rend plus silicone top coat? I've no experience of rendering and am not familiar with these products. Do they require 'specialist' skills?

Ant other thoughts would be very welcome????
 
Joh said:
Hello again and thanks for the quick replies ...

warrior .. you've hit the nail regarding the quoins. We would like to keep the existing ones .. those on the extension are set to conventional render thickness (don't want to mess with these) and at the front of the house we'd need to remove the stone down each side and replace with larger pieces .. would be quite a task. Although extra insulation is attractive, we have effective cavity wall insulation and the new-build part is well padded!

A question warrior - what would be the total thickness of the solution you suggest - ie meshed base rend plus silicone top coat? I've no experience of rendering and am not familiar with these products. Do they require 'specialist' skills?

Ant other thoughts would be very welcome????
Click to expand...

This would add about 10mm to the top of the exist render, the other option is to hack of the exist and re-render with a base rend and top with a silicone grade top coat, and yes i would advise you get a pro in, these materials are quite expensive compared to trad materials and could prove to be costly if you get it wrong , i'm sure you could get one of the lad's from here to call and give you some solid expert advice , where are you in the peaks??
 
im north yorkshire pal

im prob about 100 mile away i bet your prob closer beddy in coventry.

id suggest that shandy drinker from doncaster,there aint a lot on the rendering applications he doesnt know a lot about. warrior up wherever he is.
 
We're in the High Peak near Chapel en le Frith/Buxton .. takes me around 45 mins to get to Sheffield, so one and a half hours minimum to Doncatraz I should think??

Warrior .. I don't think we've got 10mm to play with at the quoins .. would it be a daft idea to take off the dash for the first metre or so near the quoins then grade in the base coat .. I'm guessing this would show?? We're doing a nice job on the house refurb so wouldn't want to compromise this.

We've had some of the dash hacked off near the roof line (had barge boards fitted) .. the joiner did this with hammer and chisel .. he didn't seem to take very long/have too mush difficulty .. would it be practical to do the lot without using mechanical means??
 
... and that's just how we like it! ...

But what about offering some advice - in your midlands accent, of course??
 
No mate it's not Krend this is the type off product Render Finish Conni S : Knauf Marmorit
and also then i would suggest you remove all the old dash (probs best in the long run) there are tools available now that would scutch it off without doing any real damage to the brick/int plaster , there not as violent as the older type mini breakers
Joh said:
PS what is a silicone grade top coat, warrior? Does K rend come in this category?
Click to expand...
 
What warrior says in his first post as I have come across many jobs with quoins and insulated systems would need to be minimum 80mm thick to justify the expenditure and get a decent u value. you could always remove all the old render and re-rend with a base render and then apply a coloured texture over that (if th old render is shot this would be best) otherwise use a more expensive polymeric like warrior has mentioned and keep it thin overall etc etc etc

pointer for yer; silicone based top coat to add a decorative finish to rendered surfaces commonly 1.5mm thick layer not the same as silicone krend which is a coloured mortar applied at 15mm usually
 
pointer for yer; silicone based top coat to add a decorative finish to rendered surfaces commonly 1.5mm thick layer not the same as silicone krend which is a coloured mortar applied at 15mm usually[/QUOTE]

How do you find k-rend stands up over time?
And .. if starting from scratch (as in taking off all the existing render) what products do you reckon will give the best outcome as in durable, good appearance for longest/low maintenance? (NB we are in a fairly exposed position .. would like a 'sharp' modern finish).
 
I love monocouche mate i have to say (krend and others) but it can weather but only like any other render. the problem is the manufacturers promote these products as some kind of magical solution to rendering so when they weather they get slagged off where as standard rendered buildings dont because we think oh yeah sand and cement, thats sh1te. Anyway mono will last, and is low maintenance but as an even lower maintenance spec I apply baserender at 8-15mm depending on the substrate with a top coating of a silicone texture as Warrior has mentioned there, this will resist more weather for longer but there is no truly free maintenance product - if its in britain and outside, it will eventually weather but it should last years and years done right and if I am totally honest I have never had any probs with mono and have only heard of problems where there is lots of overgrowth and trees close and overhanging to the building and certain types of tree giving of spores.
 
Joh don't think into it too hard mate alot of the heavy textured finishes are going out of date and look shite in my opinion these are the durable ones but whatever you choose I'm sure it'll last long enough for you're kids to sell the house :RpS_thumbup:
 
joh you could always just use mono cos its quick and then paint it yourself with a nano self cleaning paint in ur choice of colour whilst the scaffold is still up. These paints cover in one coat and are a couple of hundred quid well spent imo. Its the stuff kev mccloud off grand designs sticks into the mud and it comes out clean
 
Yeah I tried explaining bout the lotus plant technology to a guy on site once and he looked at me daft and glazed over so I find it best to keep such tales of alchemy to oneself
 
Thanks for you all for the advice and opinions and experiences .. I'm getting closer to a decision now (scarey!!!) .. will keep you posted
 
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