Timber framed.

[Gilesda]

Hi.
Can anybody tell me how a timber framed building or extension, which is clad on the outside is constructed? What I mean is is it built as a single frame with the cladding on the outside and plasterboard on the inside?
Or is it built like a conventional brick and block build with an inner wall a cavity then an outer wall? So two separate wood frames with a cavity between them. I hope this isn't too daft a question but it's something I haven't been able to find on the net.
Thanks.

 

[23vc]

Single frame but could also have a masonry leaf

 

[charliegolf]

The 'frame' carries the entire structural load of the house. The 'frame' is usually in UK, the inner of 2 shells. The outer can be blocks and render, stone, bricks or a mix. This outside shell is not structural- not holding up the roof, for example. Alternatively, the outer face of the frame can carry cladding fixed directly to it, which might be more timber, fibre board for rendering- anything really.

 

[Gilesda]

Single frame but could also have a masonry leaf

I've got a summerhouse or garden room, whatever it's called, bottom of the garden. It's got a solid back wall close to the fence and the other 3 walls are a 3ft high dwarf walls with windows around the top of the walls. It then has a polycarbonate roof.
All the walls are 100mm bricks, a 50mm cavity then 100mm concrete blocks inside.
I was thinking of removing the windows and roof, building it up to roof level with timber framing at the corners to reduce the window area. Then put a flat roof on it with a skylight. Either that or demolish it and start again with a timber frame from the foundations up.
At the moment it's effectively a detached conservatory and I've already got one of those that doesn't get used attached to the house.

 

[Gilesda]

The 'frame' carries the entire structural load of the house. The 'frame' is usually in UK, the inner of 2 shells. The outer can be blocks and render, stone, bricks or a mix. This outside shell is not structural- not holding up the roof, for example. Alternatively, the outer face of the frame can carry cladding fixed directly to it, which might be more timber, fibre board for rendering- anything really.

So if it's clad on the outside there is only one frame. How thick would the frame be before any boarding or cladding is attaching?

 

[bernardgreen]

The Walter Segal method is a good example of true post and beam timber framing with the insulation in the panel between the posts

This is scan of an article that describes the method of construction and the essential principle

http://www.ianwhite.info/THE_SEGAL_METHOD.pdf

 

[charliegolf]

How thick would the frame be before any boarding or cladding is attaching?

Depends on the thermal efficiency you want to achieve. Twenty five years ago, the standard for a house was a 4x2 inch frame I specified 6x2 inch. Six inch is now the norm I'd say, but I know some still build in 4". If yours is a cabin/summer house, it's up to you.

 

[23vc]

You’d need to consider insulation for the brick sections if it’s currently just got an uninsulated cavity. And is the floor insulated

 

[^woody^]

A timber frame is basically that, a frame, of timber, which is the external wall of the building. It is insulated and finished with plaster board internally as a normal wall would be.

The difference is the outer face. The frame needs to be protected from the weather and so it needs something suitable (a "rainscreen") and this sits away from the frame and separated by a cavity. This screen can be any of the traditional things you know as cladding but a brick skin is also a rainscreen - and despite it giving the appearance of a normal brick building, a brick skin is doing nothing but protecting the frame.

The frame is designed according to its purpose, so thickness varies, but typically it will use timber of a thickness according to what insulation is being used within the frame.

 

[bernardgreen]

The frame needs to be protected from the weather and so it needs something suitable (a "rainscreen") and this sits away from the frame and separated by a cavity.

In traditional timber framing the posts and beams can be exposed the weather because the timber chosen is in itself weather resistant. That said a coat of paint or creosote or bitumen was often used to give more weather resistance. Modern treatments such as pressure Tanalising and Sadolin ( other preservers are available ) also increase weather resistance of the posts.

 

[^woody^]

In traditional timber framing the posts and beams can be exposed the weather because the timber chosen is in itself weather resistant. That said a coat of paint or creosote or bitumen was often used to give more weather resistance. Modern treatments such as pressure Tanalising and Sadolin ( other preservers are available ) also increase weather resistance of the posts.

Tudor times!

Modern timber frames with the likes of 4x2 and OSB should not be confused with heftey oak post and beam frames - which may well be able to be exposed.

There is also fire resistance and spread to consider from exposed timber.

 

[bernardgreen]

There is also fire resistance and spread to consider from exposed timber.

Dare we mention exposed fire enabling cladding ?

 

[^woody^]

No. Sushhhh

 

[charliegolf]

I think he got away with it.

 

[Gilesda]

You’d need to consider insulation for the brick sections if it’s currently just got an uninsulated cavity. And is the floor insulated

The brick walls have rockwool cavity bats in them 50 thick. The floor is chipboard suspended so I can lift that and jam kingspan in-between the joists.
I want to end up with a room I can use all year round so insulation and waterproofing is something I want to get right.
I'd rather not demolish the walls especially the floor to ceiling back wall. But my proplem is attaching wooden frames to the top of 250 thick cavity walls on the other 3.
I was thinking about cladding it in vertical composite cladding. I want to take the cladding down over the bricks to only show maybe 2ft of brickwork at the bottom of the cladding.
One solution would be to extend the walls up with bricks and blocks but I have problems there. Getting a bricklayer is one problem the other is I think I'd get better insulation values in a wood frame. I don't know if what I want to do is viable though.