cement boards on timber frame

moldy_sea

Has anyone on here used cement boards on timber frame?
Experiences good/bad?
Anyone know any sites where I could see them?

Gumbo

Who is supplying you timber frame?

olestoepoke

I've used cement board on timber frames around a wet room. There are special screws for fixing it. Seen people use regular drywall screws, while they work they aren't great. There are screws with wide heads especially for cement board. Durock they used to call it in the US when I worked there. Comes in larger sheets here and is expensive

moldy_sea

Not decided yet.

moldy_sea

olestoepoke wrote: »

I've used cement board on timber frames around a wet room. There are special screws for fixing it. Seen people use regular drywall screws, while they work they aren't great. There are screws with wide heads especially for cement board. Durock they used to call it in the US when I worked there. Comes in larger sheets here and is expensive

Thanks - I was thinking more external cladding.

SC024

moldy_sea wrote: »

Thanks - I was thinking more external cladding.

yes done it numeous times with 2 coats acrylic render(sto or equiv) with mesh between coats then cement board & then ventilated cavity then breather membarane & OSB / ply etc

tfer

How much does the acrylic render cost, labour and material to install on the cement boards per sq mt. I was thinking of doing the same thing as op

Calahonda52

SC024 wrote: »

yes done it numerous times with 2 coats acrylic render(sto or equiv) with mesh between coats then cement board & then ventilated cavity then breather membarane & OSB / ply etc

how did you form the cavity?
what width?

tfer

You could batten then counter batten giving you 100mm cavity

SC024

Calahonda52 wrote: »

how did you form the cavity?
what width?

from outside in

acrylic->cement board -> 2 x 1 &1/2 batten -> breather membrane -> ply/OSB

insect mesh top & bottom

Calahonda52

SC024 wrote: »

from outside in

acrylic->cement board -> 2 x 1 &1/2 batten -> breather membrane -> ply/OSB

insect mesh top & bottom

Thanks so if its half inch gap, how were the screw holes from the CB made airtight penetrating the breather membrane, which I presume is a wind barrier?

SC024

Calahonda52 wrote: »

Thanks so if its half inch gap, how were the screw holes from the CB made airtight penetrating the breather membrane, which I presume is a wind barrier?

read my post again, not a half inch gap. the screw holes from cement board didnt penetrate the breather membrane.

Calahonda52

SC024 wrote: »

read my post again, not a half inch gap. the screw holes from cement board didnt penetrate the breather membrane.

So how is the 1/2 batten fixed to the OSB?

ps
re
read my post again

did you reflect on this before you posted it?

tfer

the batten is 50mm x 35mm, you fix the first layer at 400mm centers vertically onto the structure first and then another horizontally at 400mm center fixed onto the vertical ones

Calahonda52

tfer wrote: »

the batten is 50mm x 35mm, you fix the first layer at 400mm centers vertically onto the structure first and then another horizontally at 400mm center fixed onto the vertical ones

What I am trying to get at is how are the holes in the membrane being dealt with from an A/T perspective: its an importnat detail once you try get low A/T numbers

tfer

Your screws will be going into the studs, so no holes being made in the structure really, and its breather membrane on the outside, the air tightness membrane is on the inside of the stud.

moldy_sea

tfer wrote: »

Your screws will be going into the studs, so no holes being made in the structure really, and its breather membrane on the outside, the air tightness membrane is on the inside of the stud.

When you say studs do you mean the battens?

moldy_sea

kceire wrote: »

Who is supplying you timber frame?

Why did you ask?

tfer

I would be screwing the concrete boards onto the battens and screwing the battens onto the studs

edding4321

Hi All, any issue with self build insurance for Timeframe & cement board AND then house insurance in general with Timeframe and cement board?

Thank you

mike_2009

I can't speak to self build insurance, but last time I checked home insurance, pure timber frame is classed as non-standard building and there's a price premium - only 2 companies cover it and you are looking at 1.2K vs 3-400 per year so quite a yearly uplift! I'm going with a block outer leaf to avoid this penalty. TD said they would review in an email to me but you'd be waiting...!!