I have rotten floor joists and need to replace them, there is a wall plate in the brickwork (victorian property ) this is also bowed and rotten, can I remove the wall plate altogether and rest the new joists straight on the brickwork?
[quote="rosebery"]The answer is a guarded probably although I can't see whay you wouldn't just replace the wallplate as well. Can you upload a pic to an image hosting site and post the link to it here?
may not as straight forward as it sounds, the joists are 7x3 shared with the neighbour, on my side they are rotten plan is to cut them leaving 10" sticking thru into my side then treating them for dry rot / woodworm which leaves his floor resting on the centre wall, then I was going to use 8 x2's which allows me to leave his in between then i can insulate and board the underside the reason for the wallplate removal as i said it is rotten and bowed also it will sit to high for the 8x2 cut cut the joists down at the end but this would compromise strength and wall plate is also acting as lintels above doors and need to replace with concrete lintels, previous owners got someone to do part of it but made a mess! just want to do the job properly, do not see why you have to have a wallplate, is there any particular reason?
My understanding of timber wall plates is that they:
1 - give a nice even and level surface onto which you can lay further timbers.
2 - spread the load a bit.
3 - you can easily nail into them to hold timbers in place - either on a temporary (while fitting) or permanent basis.
I completely understand why you want to use 8 x 2 timber, and as long as you can position them accurately, and the brickwork they are resting on is sound, a wallplate is not essential.
BUT do ensure you use a damp proof membrane (quite thin, so shouldn't affect your dimensions much) between the timber and the brick.
AND install cross-pieces (dwangs) at 2-3 metre intervals along the length of the joists to stop them twisting.
8 x 2 timber may appear bomb-proof, but it is timber, and timber flexes and twists under a load - even one person standing on the floor!
And remember also to use galvanised steel straps at right angles to the run of the joists to fix the whole lot to the walls, to stop lateral movement and twisting.
And of course, try and identify why the timbers rotted in the first place, and fix the problem! It's usually blocked ventilation issues on older properties where spiders webs, plaster dust etc have built up over the decades. Make sure the ventilation points are accessible for future cleaning!
Finally give the whole lot (timber and walls) a good soaking with Cuprinol 5 star (follow the instructions!!) to prevent attack from damp etc.
many many thanks for your reply, you have answered all my questions, so now I can crack on and get the job done with confidence that I am going to do the job right.
would like to keep your name on file if that is ok ? as I have may have a couple more questions regarding some other building work I have to do as you obviously know your stuff and I appreciate you sharing it with me.
many thanks Mike
A great pleasure - and be delighted to help again if I can.
At the risk of upsetting any professionals here (I'm from the school of hard knocks!), building remedial work (at a domestic low-rise level) is a matter of observation as to the existing construction, and an understanding of some basic principles of physics - mainly leverage, gravity, water and air flow.
Common sense and Google are the most important tools in your box. And a chum to help with the awkward and heavy stuff.
One other useful pointer - don't stint on the materials you use. Let's say a builder quotes £1000 to do a certain piece of work. Every £1 he is tempted to save on materials is extra profit for him. And most of the materials won't be seen when the job is finished!
Perhaps 75% of that £1000 will be labour, which you will save if you do it yourself, so spending an extra £100 (say) on thicker, longer, wider, stronger materials, whatever, is a good investment.
You can rarely go wrong in 'over-specifying' materials. It's when you 'under-specify' that the problems start...next week, next month, next year...
Finally, and the pros certainly won't like this, these is an all-too-common expression used in the building trade: "Up high, and it won't be seen, down low, and it won't be noticed."