To stop the Bozo's from guessing!
joist thickness for loft conversion
- Thread starter jaysta
- Start date
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H
hotrod
TRADA Span Tables
Yes that's correct Tipper. I've got a .pdf of the latest TRADA span tables so it doesn't really affect me, but the philosophy sucks. Some back scratching gone on down at ODPM / Dept for Communities and Local Govt methinks, so TRADA can pimp the above tables and line their own pockets.
Thanks for the advice to all.
Hotrod you are right about the back scratching. Its the same with the NIC EIC, which I used to belong to for about 10 years, and CORGI or Gas Council. Its all a farce, there are geniune tradesmen out there who do a damn good and thorough job but cant afford to go to work for themselves any more because it cost so much to join these old boys clubs plus the mountains of beaurocracy each time you do a job. Only in this country.
I refused to pay for the TRADA tables when all I wanted was the size of one joist!
A little persistance and I found the old regs and now have pdfs of that as well as all the newer ones because it's only time until they charge for those as well!
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The old regs are on the Planning Portal for everyone to find, not difficult or hidden away at all. 
But just how long will they be there for free access and why change part A to not have the tables that everybody relied upon.
It's the same as for the acoustic requirements for flat conversions, etc, you have to pay to get the official approved designs to some tin pot quango.
It's the same as for the acoustic requirements for flat conversions, etc, you have to pay to get the official approved designs to some tin pot quango.
I told you already why they removed the tables from Part A and why should you get approved designs for free when the manufacturers paid to have them tested? Besides, there are generic designs in the regs and plenty of info on the web to get suitable designs for most circumstances approved. You could always buy yourself the same book building control use!
Hi,
I am hoping to convert my loft this Spring. Just a query, my ceiling joists are mainly 4x2, with a couple 4x3 could I coach screw, and glue another 4x2 onto the top of these to form 8x2's? If so, which would be the strongest method, running with the joists or across them? The maximum span is 4.5 mts. Comments appreciated.
I am hoping to convert my loft this Spring. Just a query, my ceiling joists are mainly 4x2, with a couple 4x3 could I coach screw, and glue another 4x2 onto the top of these to form 8x2's? If so, which would be the strongest method, running with the joists or across them? The maximum span is 4.5 mts. Comments appreciated.
I read somewhere that the process of attaching timber onto existing joists is called 'sistering' and this makes up the . I don't know if it is allowed now. I asked an architect recently, who was getting in his 50's and he had never heard of the process so I can't imagine it being very popular. However it cant be much different from 'gluebeams'. It is only my opinion but I think it is possible to achieve a satifactory floor strucure using this method but how you prove the strength is upto the required standard is another matter. Further to that the existing ceiling joists will be too far apart to comply with the standard 400mm ctrs. for 8" or 9" x 2" joists. We need some clever person to take on the building inspector with this method to prove it is not acceptable
Sistering simply means installing another joist along side the existing, then fixing one to the other, with the new joist being deeper, thus carrying the load above without disturbing the ceiling below.
Gluing a joist on top of another joist is not comparable to the 'Glu-Lam' system.
Interesting stuff.
In new installations as I understand it the new joists are not to come into contact with the old so as not to cause any disturbance to the plaster board below. The last DIY loft job I did at one of my previous houses I sat my 9"x2"'s on a 1" thick timber plate so to stand the joist off. I havent read it anywhere, I have just seen it done on many jobs I have been to in the past and copied the standard. Is there a set distance you are required to have and is it simply to reduce the noise/ disturbance between the new floor and the old ceiling???
I mentioned this on another post:-
Am I alone in using the old rule of thumb for joists as being span/thickness+2
So for a 4m or 13' opening the equation is 13/2+2 = 8.5"x2" or next size up
Am I alone in using the old rule of thumb for joists as being span/thickness+2
So for a 4m or 13' opening the equation is 13/2+2 = 8.5"x2" or next size up
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