Discussion
I'm doing a self build extension and am about to install the floor joists. There to be installed on timber to brick hangers. I know the centres need to be 450mm but can anyone help with the distance of the first joist from the wall to start the spacing?
Pictures to follow on progress if your interested.
Pictures to follow on progress if your interested.
Drawing is from the architect but this has been a balls up from the off! Damp incorrect, floor slab incorrect, insulation incorrect, block type incorrect..... the list goes on! Joists are off the shelf 200x47x3100mm. Your right about the hangers setting it off about 50mm ish.
Will the 450mm centres cause any issues over 400mm? Also I understand I need a restraint strap, what length should this be and what spacing? None of this detail is shown on the drawings.
Will the 450mm centres cause any issues over 400mm? Also I understand I need a restraint strap, what length should this be and what spacing? None of this detail is shown on the drawings.
With 450 centres you shouldn't use a 12mm plasterboard without lots of additional noggins. Also you may have difficulty with the flooring requiring H-framing under joints too.
There should be a lateral restraint strap for any section over (I believe) 4 or 5m long. This is generally fixed to the strongback supports and the hook end needs to hook into the cavity side of the blockwork. NHBC will not pass it if the strap is fixed to the internal face of the blockwork.
There are lots of diagrams and info on the NHBC website although this is something that your engineer should be setting out.
There should be a lateral restraint strap for any section over (I believe) 4 or 5m long. This is generally fixed to the strongback supports and the hook end needs to hook into the cavity side of the blockwork. NHBC will not pass it if the strap is fixed to the internal face of the blockwork.
There are lots of diagrams and info on the NHBC website although this is something that your engineer should be setting out.
Edited by Ahbefive on Sunday 22 October 20:58
Ahbefive said:
No. I used plasterboard and flooring in 2 separate sentences.
H-framing under flooring joints of required.
With 450mm centres the plasterboard on the ceiling (assuming these are 1st floor joists) will have to be 15mm and not 12mm.
Where does that come from? Do you know when it changed? Traditionally 450mm (18") was the standard spacing for 1/2" board (12.5mm now) and British Gypsum still say 450mm c/c on their website for 12.5mm thick board.H-framing under flooring joints of required.
With 450mm centres the plasterboard on the ceiling (assuming these are 1st floor joists) will have to be 15mm and not 12mm.
480mm centres work with 2400 boards if that helps? 400mm centres are always nicest though. Some people put perimeter nogs in for the boards and also nog the floor out for the stud work above.
Leave the first joist 50mm away from the wall, leave the flooring 10-15mm away from the wall.
Leave the first joist 50mm away from the wall, leave the flooring 10-15mm away from the wall.
Alucidnation said:
you shouldn’t be relying on the internet to build your extension.
I relied on it to build my first house !It can take a lot of time reading up and there is a fair bit of misinformation about - always worth a quick check with the Building Regs (which are downloadable for free)
V8RX7 said:
Alucidnation said:
you shouldn’t be relying on the internet to build your extension.
I relied on it to build my first house !It can take a lot of time reading up and there is a fair bit of misinformation about - always worth a quick check with the Building Regs (which are downloadable for free)
although I did have some prior experience. Of course as far as most builders are concerned, architects have no idea how to spec something buildable and the methods given by material manufacturers are not how they've always done it.
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