Rotten floor joist ends in brick pockets

[kilativv]

Hi!
I have a 1870s brick double wythe construction building here in US. As I was remodeling my kitchen, I found out that the floor joist ends sitting in pockets in the outside wall have rotted pretty severely. Solid masonry construction is pretty rare here in US and there's little information available on the subject, so I decided to seek advice on this forum, hoping that this kind of problem is more common in UK.

So through my research I have narrowed it down to three possible solutions:

1) Replace the whole joists completely with new pressure treated ones. This seems like the ideal way to proceed, but seems to be the most time consuming. I also have no idea how to insert the new joist into the pockets. The span is about 9ft, so the joist lengths would have to be something like 9ft 4in, but how would I maneuver them in? Also, I'm finding conflicting info whether the joist should be mortared in or left with space around it for ventilation.

2) Cut off rotten pieces and replace it with new wood, joining to the rest of the joist with angled steel repair brackets. Unfortunately, those brackets are not available here in US, but I suppose I could just use angle iron instead

3) Fill the pockets and hang masonry hangers over them instead. I dont think old bricks would work well with hangers though.

I'm open to other suggestions as well.

Thanks in advance!!

 

[ree]

Hi, before any joist cutting you must support the joist or joists further back so the the floor doesn't collapse. Support say, 50" or 60" back from the wall.

Perhaps, jack the floor to level before supporting.

Or, if cabinets are above the area of concern, or expensive flooring is down, then, without opening up, you could support, cut and make good from the crawl space - this method is not recommended for a DIY'er.

Typically, cut back 24" from the wall pocket and remove the rotted stub, and clean out the pocket.
Cap one end of a new same section, same length, piece and slip into the pocket
- cap = wrap with say a strong piece of plastic, eg a bit of debris bag from HD.

scab on (with 3/8" or 1/2" threaded rod bolts, and double sided timber connectors - Simpson DTSC/SSTC) a length(30" or 40") of same section tying in old joist and new insert.
The repaired joist tail must be perfectly level into the pocket and across the other tails.

Bolt schedule: 2" or 3" away from the joist edge, match pattern two bolts say at least 4 bolts on each joist piece.

Clean up all debris and clean out air vents.

The above is the "Bolt-on" method, there are other ways.

Come back if you need more suggestions.

 

[tony1851]

First job is to stop the cause of the rot in the first place - find and eliminate the source of the water ingress.

Cut back each joist to sound wood, and scarf with a new piece of similar section (as its an old house, the timber will probably be the full size eg a real 6x2, so you may need to get larger timber and cut down).

Splice with 3/4" plywood fixed with 3/8" threaded bar. (As the span is only 9ft, the joists won't be heavily loaded and the bending stress near the ends will be minimal, so ply will be OK as it will only be taking the shear stress).

Wrap the embeded ends in some dpc material stapled on.

Your code may specify pt timber, but if the area is kept permanently dry, rot won't develop.

Untitled

• tony1851
• 6 Feb 2014
• 1