Cedar cladding exterior wall.

[skipdiver]

A mate of mine has asked me to clad part of the front of his house with T&G cedar cladding. There is a rendered section between two brick piers running the full height if his house up to and including a gable, with an upstairs and downstairs window to go round. Seems straight forward to just affix vertical battens and off you go but not sure if i require breather membrane or not on rendered finish. There is also finishing around the windows and tackling the tiled sills, insect mesh and airflow, type of fixings etc, etc. Anyone got any pointers or websites to have a look at would be appreciated?

 

[RobinBHM]

There are good examples of timber cladding make up on the tyvek website that I have found useful in the past.

I would say you would need vertical tile battens to form a vented cavity behind the cladding. Close off the opening with insect mesh.

the windows will need larger cills probably and side cheeks.

The detailing around the window will need to be carefully done to avoid leaking behind the cladding.

Not sure about breather membrane

 

[rafezetter]

Well I would do the work in the summer, preferably after a day or two of good weather to allow the render to dry out a bit - that should reduce the chances of "trapping" moist air behind the cladding, but to be honest I doubt it'll matter unless you manage to affix the cladding in a way that hermetically seals the render. Breather membrane would only really be needed to stop water getting at the render, again overkill.

However, depending on budget you might mention this could be a good opportunity to add more insulation to the house on that aspect, you can never have enough, in which case a water membrane on top of the celotex or whatever might be a good idea and you'd have to ensure no water can get in, but still leave a gap between the insulation and the cladding so it can dry out both sides.

My father had a section of old decorative tiles redone on his house between first and second floor and added insulation underneath, he said even just doing that smallish bit meant the bedroom front wall was no longer cold to the touch and a source of heatloss.

Out of curosity has the render been painted with modern latex based paint? If so it may pay to chip it all off as painted render sometimes causes more problems with trapped water than leaving the bricks natural.

 

[johnny]

your friends best bet is to remove the rendering completely. rendering is generally applied as an attempt to waterproof a wall due to damp ingress so there is a good chance that this wall has been a source of leaking in the past especially as it sounds like it is only a partial render :wink: .

If the wall has become saturated in the recent rain it will need a chance to dry out and an inch a month is generally a rule of thumb so it will take a while. if you overclad then the damp will stay in the wall and internally your friend will still have damp and mould problems

Brick and stone is porous and most traditonal construction relies on walls being exposed and allowed to breathe so that they can dry out periodically however if the pointing is original lime mortar it may well be the source of most of the water penetration problem . if that were the case I would probably recommend hacking off the render and repointing the wall

If the building is 1930's or later it will undoubtably have a cavity in which case it would be worth hiring a borescope and looking inside the cavity to make sure that there isn't any debris or cavity fill bridging the cavity and causing damp penetration problems particularly around the windows and at the base of the wall.

If there is an ongoing mould problem around the windows (and even uPvc windows can suffer from this ) the only effective answer to this is to look at reducing the amount of moisture produced in the house from cooking and drying clothes . Placing insultion in the walls and around the window frames and reveals will only push the condensation somewhere else like carpets and clothes and furniture etc

 

[Woody2Shoes]

I might be wrong, but if you add cladding to a whole elevation (and especially if you remove the render first) you'll be expected - under building regs - to add insulation to current standards. You may also find that planning consent is needed too - it's well worth checking both. The best details are available from scouring the websites of breathable membrane and cladding manufacturers/vendors e.g. https://www.marleyeternit.co.uk/facades ... board.aspx plus a goody from TRADA https://www.trada.co.uk/downloads/publi ... adding.pdf

Cheers W2S

 

[skipdiver]

Thanks for all the speedy replies. I'd already looked at the Trada site and was going to have a look at the Marley one because i may suggest Cedral as an alternative.

Just been and had a look and although i cannot be 100% sure, it looks like the render was a design feature and not added later. Only one half of the house is done running from bottom to top and incorporating the front lounge and front bedroom windows and is set back from the rest of the facade by the width of a brick, so 4". The render looks like Tyrolean with a rough finish and is painted white. There are a few cracks in it, with one running right across the top of the lounge window about 9" above which looks lintol related. There is also a small section that has blown above the bedroom window but i didn't have any ladders to hand, so i will need to give it a closer inspection and possibly take some photo's. His house in on a busy road, so that may have something to do with the cracks as there one or two in the brickwork as well.

My mate runs a roofing company, so has all the battens, nails, insulation, membranes and laths i could wish for. We also regularly meet with the BCO, so it may be wise to have a word. He wanted it doing next week but that sounds inadvisable as things stand.

Thanks again.