An extension is being built onto a bungalow near me. The planning info desribes it as an en suite bedroom. I'm confused about the roof construction. The building is no more than 12 ft square and the pitch roof has a 10" x 4" RSJ for a ridge board and 8" x 3" timber rafters at 12" centres. This appears to be way overdesigned. I would be interested in comments. I am a time served carpenter and joiner and worked in the age when we set out the roof timbers with a steel square and built the roofs with hips, valleys etc. and I cannot work this out.
Roof Construction
- Thread starter maltaron
- Start date
Sponsored Links
If there are no ceiling ties, then that's why it's got a steel at the ridge, with the rafters bird-beaked over - the only way it can then spread at the eaves then is if the beam deflects significantly. The steel seems rather large for the load/span, though. Rafters are waaay oversized for a 2m span, as well.
Obviously "designed" by a chartered surveyor, possibly from the Brum area....
Obviously "designed" by a chartered surveyor, possibly from the Brum area....
Sponsored Links
Noooooo, quick edit your post
The problem is that many designers today just use the span tables from the approved documents for convenience, and so more/thicker timber is used than perhaps would be required.
And for the steel, they don't think about the practicalities of getting the thing up there, but rather punch a few figures into Superbeam and get a massively over designed beam - but it gets through building control.
The problem is that many designers today just use the span tables from the approved documents for convenience, and so more/thicker timber is used than perhaps would be required.
And for the steel, they don't think about the practicalities of getting the thing up there, but rather punch a few figures into Superbeam and get a massively over designed beam - but it gets through building control.
No way was that designed with design software. That's either a plan drawer, surveyor, or an office wallah doing a foreigner without PII who came up with those sizes.Noooooo, quick edit your post
The problem is that many designers today just use the span tables from the approved documents for convenience, and so more/thicker timber is used than perhaps would be required.
And for the steel, they don't think about the practicalities of getting the thing up there, but rather punch a few figures into Superbeam and get a massively over designed beam - but it gets through building control.
There are no span tables in the ADs now
.DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
