Help with painted sand cement render on timber frame (sterlingboard)

[gubsta]

Chaps,

I'm hoping you can help - and I must confess I know very little about render so please forgive the terminology.

I have a timber framed house and am replacing the windows. At the same time I also want to get rid of the mock tudor. This will obviously leave bits of the facade which need 'filling in'.

Now before I start I would add that if the house was block and brick I would happily remove all the old render and start again. But because the render is on Sterling board this approach will I assume destroy the sterling board

The render itself is very well bonded to the house (it is 20 years old), but water is getting in-between the mock tudor timber and the render - this is resulting in the paint peeling off the render.

I have had lots of conflicting advice on how to address the render repairs once the windows are replaced.

I had one chap who said he'd just whack a new top coat of sand and cement over the textured painted finish. I did ask him how he expected render to stick to paint when the paint itself was peeling off but he didn't seem too concerned!

I have a local builder who I trust who said you would have to key the existing render in some way (or screw a mesh to it) and then put a whole new sand/cement top coat on. He was also going to replace all the beading too. This is coming out much more expensive than I expected though.

What I really want is a finish that doesn't require painting and offers the improved weather protection that modern acrylic renders offer.

So my question to you as experts is - what would be the best approach to get a modern maintenance free coloured render finish over the top of the existing sand/cement?

As the textured paint is so thick - do you think this would hide any render repair in the 'filled in' bits? Or is that asking for trouble?

I've attached some pictures of the house below so you get a feel.

Sorry for epic post - thanks in advance.


P1020804 by Gubsta, on Flickr


P1020803 by Gubsta, on Flickr


P1020802 by Gubsta, on Flickr


P1020801 by Gubsta, on Flickr

 

[beddy]

I'm no expert in modern renders but you could remove the existing boards. Fix a render carrier board and apply a thin coat system with a coloured acrylic topcoat.

 

[beddy]

Or, depending on price difference between the two. You may be able to locate the timbers, fix insulation board over the existing render and apply the thin coat and acrylic. This has the added benefit of insulation but I do not know what the difference is in price per metre compared to render board. Obviously you'd save labour and mess by using the insulation rather than taking it back to the studs

 

[Runswithscissors]

Hi Gubsta

Thanks for your post..... but it kind of leaves lots of options open.....

1 - remove the whole lot, re install a modern render carrier board and thin coat render system, seal into the timber as you go.

2 - Clean off all the paint, have a render specialist inspect the exisiting and carry out any repairs, then apply a modern finish over the top. Something with a 1.5mm grit ot heavier should cover any quality repair

3 - as Beddy has said - you could have someone come out and check the frame and structure and investiage getting a new Insulated Render System (EWI - Eternal Wall Insulation) applied. There are a lot of grants and deals on the market at the moment so look around and do some research - ask for more info openly on here and some specialists will help point you in the right directions. They will need to be able to secure the insulation back to the frame, or get certainty that the existing backing is secure to bond to.


Where are you based? maybe let us know and leave an E mail address for someone to contact you to arrange a meeting to discuss further.

By all means contact me ref item 1 - or, for contact of some specialist render system suppliers to contact in your area..... all my contact details can be found on my profile - click on my profile name, top left, and then click on the my profile part.

Good Luck!

 

[gubsta]

Thanks Beddy and RWS.

I should have probably said that I have looked into removing the outer skin and replacing with an EWI system. The budget quotes I've had back have been eye watering - although I do think that would be the right thing to do. At the moment there is a ~£10k saving to go with a new coat of sand and cement over the keyed render. There are a load of dormas which add complication.

Beddy - as for the fixing of a new insulation system over the top - I have discounted this as the increased facade depth would obscure the ventilation for the roof - leading to the retrofitting of a load of ventilated tiles. It doesn't stack up from a cost point of view.

RWS - If I go for the remove the whole lot option I will go with some form of insulated system. I had ruled out just replacing the existing with a carrier board and thin coat as I thought it would probably not satisfy building regs in terms of upgrading thermal elements (L1B). I haven't done the u-value calculations yet though.

So my primary options are rip it all off (including the existing carrier board) and go for a new cavity EWI system or a 'patch and new top coat' solution of some sort.

It was cost really that led me to investigate the non-EWI option further. It's good to know you think there would be some form of modern finish that would go over the top.

I'm based in Bucks - my email is myforumusername at yahoo dot com. Would be very interested to hear from anybody who might be able to help!

 

[beddy]

What depth have you got to play with? Insulation can come as thin as 25mm although obviously this wouldn't be as effective as 75mm

 

[plasterjfe]

What depth have you got to play with? Insulation can come as thin as 25mm although obviously this wouldn't be as effective as 75mm

I think it needs to be 30mm min to receive and carry render for suitability and long term integrity unless its a reveal board

 

[beddy]

Didn't know that. Like I said I'm no expert and have only learnt the basics off here.

 

[warriorupnorth]

as echoed above , stripping back and starting again would be more advantageous and more cost effective in the long term, and as said there is some funding available dependeant on the level of insulation already incorporated in the original build, it may be worth getting an epc done with extendeded sap calcs to see what savings can be made long term and look at the eco funding or at worse green deal funding ,Contact a local GDP and ask there advice,
Personally i would strip back and re-insulate and sort out all the detailing , especialy around the dormas, windows, and down onto the brick/tile plinth, this would ensure the scheme being robust enough to last out your lifetime and minimise any future maintenance , if any

 

[malc]

if you want the cheapest , i would remove the mock tudor timbers, rib lath and render in sand and cement.