Need to make loft hatch bigger(CUT 2 JOISTS???????)

[sparky1508]

Hi everyone

I'm fitting a new loft hatch for a friend but the one they want is 111cm x 55cm and the existing hole is 77cm x 61cm and already cut through one joist.I'm not worried about the width as it will only take a bit of adjustment to make it fit that way but was wondering if its possible to cut through another joist to make it fit on the long. i know about putting a peice of timber across the joists to support them until they are braced correctly. The roof structure does have collar beams too so i'm thinking it might be ok to do. Any advice welcome.

thanks

any advice please

 

[sparky1508]

Is there anybody out there that has knowledge of this kind of thing?

 

[masona]

Is it a gang nailed trusses?

Any photo?

 

[sparky1508]

Not really sure what that means but i don't think its got those plates that hold all the timber together and there is a collar beam every 2.Sorry haven't got photos but there is a wall at 1 side of the existing loft hatch which will support that side. Was thinking if i double up on the trimmers it would be strong enough to support 2 cut joists. Will try to get some photos.Also its just diagonal roof beams with vertical timbers running down from each one. very big open loft space.

Thanks for the reply

 

[masona]

Got this plate on every joints?

If so, then you can fit a bigger loft trap providing it's within the trusses without cutting any part of the trusses timber, these trusses are designed to use less timber to save weight and cost so can't be cut without checked by an experienced carpenter, an engineer or the roof trusses company maybe able to advise you, you mustn't cut any part of the trusses as it could weaken the roof structure. The old properties type non-gang nailed roofing are okay to modify if done correctly. Having said that, it can be done by re-designing correctly

If it's the non-gang nailed type then a photo's would help us to help you

 

[sparky1508]

Thanks for your reply.
No it hasn't got those just the roof beams and uprights at either side with coller beams joining one side to the other. Not sure but think they are called king pins or something. One joist is already cut through for the existing hatch but the new hatch is longer and so needs to be cut through another joist. Would it not be ok to just cut another joist as long as i brace them properly until i get the structure in for the loft hatch and if i double up on the sides with the cut timbers would it be strong enough?