Dry rot on joist ends

[mazears]

I have dry rot on at the ends of 3 floor/ceiling joists (also on the internal wooden lintel) They seem quite crumbly and soft. I have some dry rot water based treatment (one for wood/one for mortar).What would be the best course of action? A builder friend advised to prop the joists then cut the bad ends off 6ins. He said to put joist hangers on inside of the good joists either side of the 3 to be cut,and hang a new piece wood across.Then attach the 3 cut ones to the new piece with a further 3 joist hangers. Would this be acceptable?

View media item 16445
View media item 16446

 

[noseall]

How much rot damage is there to the joist ends?

Are you sure it is dry rot?

 

[mazears]

The 1st (towards left) of the 3 bad joists seems to be the worst. You can see where i've hollowed it out. I've had a screwdriver in it and it breaks away probably 2in deep from bottom end. I could maybe break it all away if i tried. Other two can be chipped away from bottom end but not half as bad. All 3 joists rest on the inside brick although at present they are just sitting in mid air and not on the brick-hence a slight spring in upstairs bathroom. Right hand side of the lintel is extremely rotten also. I posted a question in this forum previously and was advised it was dry rot as opposed to wet rot. Was hoping i could simply paint on the dry rot treatment but think 1 or all 3 may need cutting off?

 

[gregers]

the preservation industry will state that any evidence of dry rot will need to be removed.
1m in all directions where feasible.past the last found evidence.
i think you will have to cut out a lot more then you think,then maybe do a trimmer/trimming situation using the jiffys where needed.
the masonary will need to be drilled and sprayed with a masonary fungcide(dry rot fluid).
any timbers left i would surface treat with something like probor 20,which is a deep penertrating paste/gel.

why not phone up a treatment specalist to advise and see how much it will cost to treat and gaurantee (peace of mind).

also bear in mind,THAT IF IT IS DRY ROT,because it is close to the timber lintol then it may be in there as well,think you need to investigate a lot furthur.

 

[mazears]

I was intending taking out the timber lintel and replacing with concrete one. Bricks above and around this area need removing and securing again (maybe i can discard these bricks and use others if they are a potential problem with the dry rot? I bought a suitable timber treatment and a treatment for masonary from permagard (5litres of each that you paint on). Sounds like the joist hanger scenario is ok but you recommend i cut 1m off each joist end? Sounds alot as kitchen is only 2m wide

 

[stuart45]

You also need to find out what caused the timber to get damp and correct the problem.

 

[gregers]

i defo think you need to gain advice from a reputable preservation company to give you the advice thats needed,painting on the solution is about as much use as a chocolate fire gaurd imo,you need a decent hand pump at least to make sure you are getting the solution into the building fabric painting it onto the timber will be ok to a point,but it will need to be done at least a couple of times.

what i have suggested was/is what we used to advise customers,wether that has changed i do not know,take a look on google and read up on the info about dry rot.

 

[mazears]

The damp is either from the bad external rendering or from bath directly above. Property has been empty along time and had no ventilation

 

[Deluks]

Still just looks like wet rot to me.

 

[maltaron]

No sign of dry rot. Dry rot is a fungus and if it was in the joists and the lintol there wold be black cobwebby strings all over the brickwork and timbers, and the timber would show as broken up in squares. Its almost certain to be wet rot and whether dry or wet you will need to find the source of damp.

 

[Nige F]

A year later it`l be collapsed anyway

 

[ianblue]

The damp is either from the bad external rendering or from bath directly above. Property has been empty along time and had no ventilation

This is the first thing you need to address. Where is the dampness coming from? Rot can only take place when the wood is carrying excess moisture. If you remove the water supply, the fungus will die. Any piece of wood will have fungus spores present, waiting for the correct level of moisture to start growing.
Obviously the weakened timber must be removed and it makes sense to coat new timber and adjacent timber to prevent further problems ie if the dampness re-immerges.