knackered floor joists

[vicky whitworth]

Yet again I'm after some advice. The floor joists above our scullery were described as 'beyond saving' on our strucutural survey and since then a structural engineer has said that we shouldn't be walking into the room above as the whole lot is likely to collapse. Mind you that was two years ago and my 16 stone OH uses the room every day but there is certainly a lot of movement in the floor (it makes me feel slightly sea sick to walk over it) and downstairs in the scullery where the joists are exposed we can see that they are 1) riddled with old worm holes 2) broken in places 3) do not reach the walls on either side. There has been a bit of patching over the years but to be honest the 1x1 bits of timber someone has screwed up are a bit pathetic. The room above used to be a hayloft and we suspect that the joists have rotted from having damp hay on them. We think the floor joists date to about 1800 but it could be a bit earlier. The timbers are weedy abaout 3x4.

We have a builder scheduled to replace the whole lot - new joists, new ceiling (currently ceiling is made up of something I think is called fibre board - nice!) but I would like to try to save as much of the timber as possible - possibly by scarfing (!) new timber into the ends of the old ones (although I'm not sure there is even sufficient solid timber to do this).

Has anyone had any similar experience or could recommend anything? Many thanks, Vicky

 

[Schoolmarm]

I can't help with advice on saving timber but have to say this. Please put some whopping great joists underneath and prop it all up with acros if you are going to keep walking on it. It is quite a vivid description you have given of the complete set up and it really does sound bad.

 

[Penners]

Vicky - if the joists are beyond saving, and a structural engineer has warned you not to walk on the floor above, are you sure that it's worth scarfing in new joist ends? If the joists have been rotted by wet hay in the room above, presumably the rot is not limited only to the ends.

What timber are the joists? Are they fine and important? Is the building listed?

Unless you're doing a DIY job, then scarfing in new ends is probably going to be considerably more costly than putting in a new set of joists, and unless you're entirely confident that the rot is limited to the ends only, you still may not end up with a safe structure.

If you're keen to conserve the old joists, why not put new ones in between the old ones, so you've got the security of new timber but you've conserved the old?

And by the way, I agree with Schoolmarm.

 

[chuckey]

3" X 4" @ 16" centres, good for 6' span ? As a compromise buy secondhand joists. The ends of my joists rotted off due to the holes in the roof! (6" X 2" @ 18 ", 9' span)
Frank

 

[DaveBrigg]

I repaired joists in one bedroom which had rotted where they were attached to an outside wall. The replacement timber was a similar dimension to the joist. The joist ends had all loose material removed, and old and new wood was given a libral treatment of wet/dry rot prevention. The new pieces were bolted onto the sides of the old using some fairly hefty coach bolts, with about 3ft of overlap. I'm not sure if this is the recommended solution, but it has stayed firm so far. The rot was confined to the last six inches of the joist though, and there was no woodworm.
The problem with this is that the new pieces do not line up with the holes in the brickwork where the old pieces used to be, so there is extra work involved in cutting new slots. It's not the prettiest method of repair either, but with the floor boards put back down and the ceiling below patched, no-one will see.
Although your floor can currently take the weight of one person, there may come a time when you want to put in some furniture and invite the neighbours round to see the renovations. I imagine there would be a few red faces if you all suddenly found yourselves on the ground floor again. If the structure had already been condemned, you wouldn't have a leg to stand on...

 

[FamilyWiggs]

If the structure had already been condemned, you wouldn't have a leg to stand on...

Particularly as they had both been broken in the fall.

Sounds to me like the existing joists need completely replacing with new/reclaimed timbers, according to your preference. I've just put new oak in, and whilst expensive, they look fab.

You go from 'orrible 1970's varnished fake beams like this:

View attachment 2

via this:

View attachment 1

With this being the end result. You also get the chance whilst you are doing this to correct some of the uneveness (if you want to) in the floor level/curvature above.

 

[FamilyWiggs]

And here's some of the detail. You can see how we levelled the floor above a little, but raising the top edge of the joists at the "lower" end of the cross beam. (BTW is this what a "trave" is?)

View attachment 1

And this is what you get is you scarf in new timber to retain old beams whose ends had rotted away. You can just see the lovely dry-lining and tanking in the room above. the whole bloomin' house was like this! Slowly ripping it all out, and lime plastering in its place.

 

[KayW]

Loving your pics familywiggs what a great job you are doiing :wink: :wink: :wink:

 

[Penners]

That's a fine job you're doing there, FamilyWiggs. Lovely to see new oak being put in.

I have one small suggestion that may or may not be relevant, depending on your ceiling plans. When I did a similar job some time ago, I fixed the counterbattens to the side faces of the joists before I installed them. It does make life a hell of a lot easier.

 

[Penners]

Incidentally, yes, I've always understood a trave to be a crossbeam. Sometimes also called a king joist, I believe.

 

[vicky whitworth]

Thanks guys for the advice. Wonderful photos Family Wiggs. I can see the old joists will have to go. Perhaps we can salvage just some of the timbers and re-use anything that looks solid (not sure there's much though).
Builder's just rung to say he can start in two weeks so rather over-excited now. Two-storey kitchen and bathroom extension going on. Have had no kitchen for two years so am very looking forward to the future. Vicky