Repairing Rotten Joist

[Paul]

The side of my house is kind of chalet style - the ridge of the roof starts at the normal two storey height, and then comes down to a height of about eight feet. Hence, there are long joist runs supporting roof tiles.

I noticed this weekend that the lowest two feet of the fascia board just under the rood (soffit board?) is rotten. I removed this section of board, and the joist just behind the board is also rotten on it's outside edge only - again, just the bottom two feet of joist. I assume this is wet rot, it's black in places, and I'm assuming water can get in by running off of the edge of the tiles and then running 'upside-down' into the crack between the top edge of the soffit and the underside of the roof.

I would imagine repairing/replacing the rotten section of joist is a major undertaking. But given that it is only the outer edge of the joist that is rotten, can it be repaired please? My ideal would be some sort of stabilising solution, like fibreglass resin perhaps, or maybe there is some proprietry solution for this? Second favourite would be to cut back the rotten part, and screw in a new piece onto the unaffected timber, but I'm not sure how effective this would be.

I would very much appreaciate any suggestions.

Thanks,

Paul.

[Dave Fawthrop]

| The side of my house is kind of chalet style - the ridge of the roof | starts at the normal two storey height, and then comes down to a height | of about eight feet. Hence, there are long joist runs supporting roof | tiles. | | I noticed this weekend that the lowest two feet of the fascia board | just under the rood (soffit board?) is rotten. I removed this section | of board, and the joist just behind the board is also rotten on it's | outside edge only - again, just the bottom two feet of joist. I assume | this is wet rot, it's black in places, and I'm assuming water can get | in by running off of the edge of the tiles and then running | 'upside-down' into the crack between the top edge of the soffit and the | underside of the roof. | | I would imagine repairing/replacing the rotten section of joist is a | major undertaking. But given that it is only the outer edge of the | joist that is rotten, can it be repaired please? My ideal would be some | sort of stabilising solution, like fibreglass resin perhaps, or maybe | there is some proprietry solution for this? Second favourite would be | to cut back the rotten part, and screw in a new piece onto the | unaffected timber, but I'm not sure how effective this would be.

Treat the rotten bit, and the good joist behind it, to stop the rot spreading. Fasten a new bit of treated joist to the side of the old one.

[Dave Liquorice]

After finding out why the rafter (joists is under floors...) is getting wet enough to rot and curing that source of damp. It shouldn't be getting wet at all.

[Set Square]

I presume that you are talking about the sloping timbers which are part of the roof - in which case they are rafters rather than joists. These are structurally significant since they are supporting the not inconsiderable weight of the roof tiles. The rafters are supported by wooden wall plates on top of the brickwork, and then extend beyond the brickwork into the soffit/facia area.

The rafters need to be really solid to at least the point where they rest of the wall plate. If the rot extends upwards beyond the wall plate, you have a major task on your hands. If the rot is only in the part below wall plate level, you can simply cut off the rotten part and bolt some new rafter extensions to the side of the solid part.

You will have to remove several rows of tiles, and the battens under them, and peel back the felt to get at the affected parts. It sounds to me as if the felt has perished. This should extend down under the tiles and just into the gutter - preventing rain water from getting anywhere near the woodwork. So you'll probably have to renew the botton strip of felt, sliding the new stuff up under the extisting felt so that drainage works in the right direction.

[meow2222]

not necessarily.

For the rafter to be getting wet you usually need 2 faults: tiles not working and felt not working. You may be able to replace a broken tile without having to take anything more apart.

You'll then need to support the tiles properly, as with snow on them they get seriously heavy. I dont know what access youve got, but since its rotten you might be able to cut the rafter above the rot then split the rotten bit off, then bolt new wood onto the side. If so, you may be able to avoid lifting a section of tiles this way.

But beware, if the rafter is supporting anything at all, it _must_ be supported securely before cutting anything away. This can usually be done with a well secured cross piece, spreading the load onto neighbouring rafters. Realise the cut rafter must be properly secured, no way can it just rest on the crosspiece. If in doubt, dont, as the rafters do hold the roof up.

NT

[Paul]

Thanks for all the replies, that's all very useful; I've had to put this on hold for a while as my wife is in hospital after an accident since posting. Perhaps I can put up a picture so that it is clearer what I mean.

Thanks again all,

Paul.

Paul wrote:

[Set Square]

Sorry to hear that. I trust that she didn't fall off a ladder while mending the roof?

[Paul]

Oh no :). Much simpler, slipped on a paving stone in the street. Still managed to break the ball off the top of the femur though :(.

Regards,

Paul.

Set Square wrote:

[Rob Morley]

You can get a repair bracket for that - a steel strip that screws to the outside of the shaft, with a BIG screw that goes through the neck of the femur to hold the ball in place. I've got one kicking around here somewhere :-)