I've got a sagging joist (3 " x 4 ") above a bay window. I've only got about 3 1/2 inch drop before the top of the window so I can't get an rsj underneath for support. Any suggestions please with regards to what I can use to support the existing joist without complete replacement?[/u]
How to support an existing joist?
- Thread starter oscarinnes
- Start date
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Hopefully with a 3x4 timber it's not too big a span.
Could you slip a 4x4 steel angle under it?
Could you slip a 4x4 steel angle under it?
Forgot to mention that the span is 3m pillar to pillar. I've only really got 3 to 3 3 1/2 inch drop before the top of the window. Not exactly sure what a steel angle is?
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What thickness of steel angle would be needed and where to get one?
The problem that I foresee with this solution is that the dip in the joist goes underneath the horizontal of the underlying brickwork - so unless the joist is forced up (possibly cracking the ceiling plaster) then I'm not sure how to get it under for support?
The problem that I foresee with this solution is that the dip in the joist goes underneath the horizontal of the underlying brickwork - so unless the joist is forced up (possibly cracking the ceiling plaster) then I'm not sure how to get it under for support?
What you may be looking for is a flitch plate. Its a flat bit of steel that is screwed/bolted to timber to give a greater combined strength "Flitch Beam".
Speak to a steel fabricator and they should know what you are on about and they can pre drill it for you.
Speak to a steel fabricator and they should know what you are on about and they can pre drill it for you.
The size and thickness of the angle would depend on the span and the load the timber beam is carrying - is this an upstairs bay roof by chance?
If it's just a bay roof, on that span I suspect you would be looking at a 4" or 5" deep angle; you get them from steel stockholders - sometimes they have 2nd-hand items.
Yes, you'd have to jack it up some way and it may crack the ceiling, but if you want it reasonably level..............?
If it's just a bay roof, on that span I suspect you would be looking at a 4" or 5" deep angle; you get them from steel stockholders - sometimes they have 2nd-hand items.
Yes, you'd have to jack it up some way and it may crack the ceiling, but if you want it reasonably level..............?
I can confirm that it is an upstairs bay. When we bought the house 4 years ago we took down all of the upstairs lath/plaster ceilings as they were past it. We then reboarded and skimmed so this (new) ceiling has been in place for at least 3 1/2 years without further cracking - which suggests that whatever movement there was has pretty much ceased. The room then became my tool room until last week as I've now cleared it out with the intention of getting it ready for the little one to move in before Xmas. Consequently, I would like to avoid replacement of joist and/or redoing the ceiling plasterwork if poss as I i don't have as much time as I'd like to get the room ready. Perhaps the flitch plate may be the best solution? I have uploaded images of the joist if it helps. Thanks for the advice.
Looking at your photo's I think you have got the "joist" size wrong. I think you may only be looking at perhaps a third of it with the rest disappearing into the space above the higher ceiling.
You will not be able to straighten that out as it will be far to substantial. The reason for the deterioration at the end needs to investigated and dealt with but given the likely size of the timber probably still OK.
If a plate was fitted it would need to be deeper and slipped past the higher ceiling. access from above would be extremely difficult due to the eaves unless you have a gable on that elevation.
I would take out the "curve" by planting on to the underside of the beam some timbers planed to a taper to suit. Add some flat packings to the bay joists to level that part with the lowest point of the beam.
Timber does undergo deformation due to long-term creep, so if it's a substantial section, you may not be able to jack it without lifting the ends.
As Blagard suggests, perhaps try and mask it?
As Blagard suggests, perhaps try and mask it?
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