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"A" frame joist problem

Posted: Sun Mar 15, 2009 10:50 pm
by Martin68
Hi, I have a very old detached house, I want to slowly (as i can afford it) convert the loft into a play room/ home cinema.
The roof structure consists of 2 thick wooden "A" frames and perlings going horizontally accross, supporting the thinner roof beams, the structure is devided into 3 sections with the "A" frames on each 1/3

I have dropped the cielings down by 6 inches about 10 years ago while i was removating my house, i did this with the thoughts of maybe wanting to convert the loft in the future.

Now my loft has plenty of head room, but the two "A" frame structures still have a horizontal 7m long brace beam (which used to be part of the ceiling joist) going accross too high.

Can this beam be cut away by first adding a lower beam to the "A" at the correct hight and will form part of the floor/ceiling?

Posted: Mon Mar 16, 2009 12:28 am
by rosebery
The obvious answer is no unless you want to risk your roof falling down.

I think you should consult an architect or structural engineer and he will need to look at it physically.

Cheers

A frame problem

Posted: Mon Mar 23, 2009 5:05 pm
by bigtone
As the man says, thats a big no no unless you want your roof to collapse. The reason for that beam is to hold the frame together. If you think of the letter 'A' as the frame. Take away the horizontal part of the letter (i.e. your 7m beam). Then add some weight to the top of the letter 'A' (i.e. your roof tiles. What happens to the letter 'A'? Yes, it collapses.

You have to somehow tie the bottom of the roof rafters into the building to stop them splaying.

Posted: Tue Mar 24, 2009 3:25 pm
by Dibble
How far up is the tie beam or collar? If there is room below it to fit new collars then the answer is yes, you can cut away the old collar. The first step would be to find out what size timbers you would need. These would have to be fitted in pairs, either side of the main spar of the A frame and bolted through. Once fitted, you would be able to cut away the old collars. For such an important job, get local advice.