Hello,
I have an older house with a partial crawl space foundation where the sill, beam, and floor joists have been locally affected by water and insect damage... Fortunately, it is limited, and I have cast a pillar to transition the beam, so it only needs to be about one meter long, and the joists that are damaged can then transition over the new beam, so they only need to be about 1.5 meters long.
But even if I don't need much wood, my problem is that the wood is in "inch" dimensions:
Is it OK to glue and nail two 45 x 220 to achieve a 90 x 220 beam instead of 75 x 225?
The same goes for the joists, is it OK to glue & nail two 45 x 170 to get a 90 x 170 instead of 75 x 175?
In both above cases, I intend to use C24 grade joists.
Or is it better to buy a 90 x 225 glulam beam and use both as a beam and cut it down to 90 x 175 for joists? The damage is so far (as I have seen) so limited that a four (or maybe six) meter beam from Bauhaus could suffice for both the beam and floor joists, so money isn't decisive.
The advantage of using double standard joists is that it becomes a bit easier to join with the existing beam/joists since I can let one of the joists overlap by a meter and nail and glue it to the existing joist.
Or is it even possible to get hold of three-inch (75mm) wood somewhere these days?
I have an older house with a partial crawl space foundation where the sill, beam, and floor joists have been locally affected by water and insect damage... Fortunately, it is limited, and I have cast a pillar to transition the beam, so it only needs to be about one meter long, and the joists that are damaged can then transition over the new beam, so they only need to be about 1.5 meters long.
But even if I don't need much wood, my problem is that the wood is in "inch" dimensions:
- The beam "three-by-nine" (which measures 75 x 225 mm).
- Floor joists are "three-by-seven" (which measure 75 x 175 mm).
Is it OK to glue and nail two 45 x 220 to achieve a 90 x 220 beam instead of 75 x 225?
The same goes for the joists, is it OK to glue & nail two 45 x 170 to get a 90 x 170 instead of 75 x 175?
In both above cases, I intend to use C24 grade joists.
Or is it better to buy a 90 x 225 glulam beam and use both as a beam and cut it down to 90 x 175 for joists? The damage is so far (as I have seen) so limited that a four (or maybe six) meter beam from Bauhaus could suffice for both the beam and floor joists, so money isn't decisive.
The advantage of using double standard joists is that it becomes a bit easier to join with the existing beam/joists since I can let one of the joists overlap by a meter and nail and glue it to the existing joist.
Or is it even possible to get hold of three-inch (75mm) wood somewhere these days?
Inch measurements can be obtained if you have a local sawmill nearby. But I have seen before that you can order it from XL Bygg at least. The question, however, is whether it becomes much cheaper than buying a larger beam that you cut yourself. Gluing together is a less sturdy construction than a whole piece. It works well as a sill where there is a supporting wall all the way underneath, but I would never do so where there are point loads without support underneath.
If you are primarily looking to replace the rough-sawn timber with wood of the same stiffness, you can use glulam. Replace 3x9 inch with 66x225 and 3x7 inch with 56x180.
Judging by your name, you live in Gothenburg. Holgers in Borås sells rough-sawn timber, they might be able to provide your dimensions.
Hmm. that was interesting. I am neither an engineer nor a carpenter, so I am not sure if or how much stronger/stiffer glulam is compared to regular wood, hence my thought to always build in larger dimensions than the original. It's still such a small amount of material that the cost won't be decisive, and there is space in width. But if it is the case that I can use "standard" dimensions that are easier to source, that would be good in terms of time.J justusandersson said:
- Does 66x225 glulam have the same load-bearing capacity/stiffness as a 3x9 inch (75x225) wooden beam?
- 56x180 glulam is a bit too "high" so I would have to notch out 5mm at the supports, can it really replace a 75x175 wooden beam?
You're right, the width is free, so to speak. The carrying beam only has air on the sides, and the hole in the wall where it should go in is about 12 cm wide, so there's space. Between the floor joists, there's only insulation (sawdust today...), so the width can vary there too.A andersmc said:
It's only in height that it needs to be roughly correct, but for the carrying beam, I can adjust the supports slightly upwards and I will probably need to tap in leveling shims anyway to get it tight, so... Also, I already have suitable C24 joists at home, hence why I'm wavering a bit back and forth.
However, I saw that Beijer had four-meter 90x225 laminated beams nearby for 890kr, so perhaps I should go with one of those anyway.
The glulam dimensions I suggested have the same capacity as your original rough-sawn ones. I have assumed that your old beams have a strength comparable to class C24. A 5 mm notch at the supports is insignificant.
Good to know that I can reduce the dimension of the long floor joists if the insects have eaten more of them than I have seen so farJ justusandersson said:
However, I looked around during the day for where I can get timber and ended up at Beijers; they had 90x225 glulam in stock and 10% off everything in stock, so I went for one of those. It certainly won't be undersized
It will definitely be really good!