Went through the drawing materials for our house and found a question mark (should be ok, but...)
Conditions: Crawl space foundation consisting of an outer wall and a support wall in the middle of the house, total width = 8.1m, i.e., 7.7m internally.
According to the Lathunden, the maximum clear span with 2 bays and K24 45x220 as floor joists with glued 22mm particle board is 6.7m.
Interestingly, if you look in the Wood Construction Handbook (part 5, foundations), the maximum clear span is stated as 7.3m under the same conditions.
Anyway, the existing construction doesn't seem to meet any of the rules.
I get the impression that this shouldn't be an issue; most houses I've seen with crawl space foundations have similar foundational structures, and houses narrower than about 7m are rare.
Anyone who has experience with similar constructions?
Conditions: Crawl space foundation consisting of an outer wall and a support wall in the middle of the house, total width = 8.1m, i.e., 7.7m internally.
According to the Lathunden, the maximum clear span with 2 bays and K24 45x220 as floor joists with glued 22mm particle board is 6.7m.
Interestingly, if you look in the Wood Construction Handbook (part 5, foundations), the maximum clear span is stated as 7.3m under the same conditions.
Anyway, the existing construction doesn't seem to meet any of the rules.
I get the impression that this shouldn't be an issue; most houses I've seen with crawl space foundations have similar foundational structures, and houses narrower than about 7m are rare.
Anyone who has experience with similar constructions?
An attempt to clarify:
According to the dimension criteria found in, among other sources, "Lathunden- Hjälpreda för bygghandels personal och kunder," the maximum length (L) is specified as 6.7m for floor joists consisting of K24 timber with dimensions of 45x220 and laminated floor chipboard on top.
The question mark was that our house has L=7.7m, i.e., a bit over the recommendation. Therefore, I wondered if anyone here had experience with similar solutions or if our house is "misdimensioned"?
As mentioned, I don't think this is a problem, just a deviation that one might be able to live with (unless you're planning to lay tiles).
According to the dimension criteria found in, among other sources, "Lathunden- Hjälpreda för bygghandels personal och kunder," the maximum length (L) is specified as 6.7m for floor joists consisting of K24 timber with dimensions of 45x220 and laminated floor chipboard on top.
The question mark was that our house has L=7.7m, i.e., a bit over the recommendation. Therefore, I wondered if anyone here had experience with similar solutions or if our house is "misdimensioned"?
As mentioned, I don't think this is a problem, just a deviation that one might be able to live with (unless you're planning to lay tiles).
No, I actually understand exactly what you mean. Exactly, even 
(I wonder if I've asked that question here myself at some point!) It's a completely correct observation that the Timber Construction Handbook and the Pocket Guide don't match. However, I made the same reflection as you: there are few houses that are as narrow as 7 m! I asked the question to my KA, who in turn contacted a structural engineer (otherwise, I am my own structural engineer ). He looked at my drawings and then gave the go-ahead for my solution, provided that I reinforced between the beams at about 2, 4, and 6 m. However, I wanted a screwed grid panel on top of the beams to lay underfloor heating in. That was NOT allowed because the grid panel doesn't provide load interaction with the beams. A screw-glued floorboard was required. The user marge here on the forum, however, has 8-meter beams with a grid panel. She can probably explain the result if you ask.
(I wonder if I've asked that question here myself at some point!) It's a completely correct observation that the Timber Construction Handbook and the Pocket Guide don't match. However, I made the same reflection as you: there are few houses that are as narrow as 7 m! I asked the question to my KA, who in turn contacted a structural engineer (otherwise, I am my own structural engineer ). He looked at my drawings and then gave the go-ahead for my solution, provided that I reinforced between the beams at about 2, 4, and 6 m. However, I wanted a screwed grid panel on top of the beams to lay underfloor heating in. That was NOT allowed because the grid panel doesn't provide load interaction with the beams. A screw-glued floorboard was required. The user marge here on the forum, however, has 8-meter beams with a grid panel. She can probably explain the result if you ask.Also have short beams at 2.4 & 6m (45x170), not sure if the floor chipboard is glued or not (the downside of old houses, you don't know what it looks like underneath until you've taken a little peek ;D).
It will be fun in the future as we are planning to install underfloor heating on the entire ground floor. We might have to install the underfloor heating recessed in the joists (tear up the floor and groove out the short beams :) alternatively install the underfloor heating on the chipboard (lose ceiling height)... we'll cross that bridge when we come to it ... have enough projects as it is right now.
It will be fun in the future as we are planning to install underfloor heating on the entire ground floor. We might have to install the underfloor heating recessed in the joists (tear up the floor and groove out the short beams :
) alternatively install the underfloor heating on the chipboard (lose ceiling height)... we'll cross that bridge when we come to it ... have enough projects as it is right now.or buy tracked chipboard floor panels. More expensive, yes much, but in relation to saved hassle I think the price difference will be negligible!
Do I understand correctly that the kortling you are talking about here has the same function as krysskolvning?
Yes, traditional crosshead work is probably performed very rarely nowadays. My scarred CA chuckled contentedly when the subject came up.
Yes, you are actually cycling. ;D I also reasoned that if four meters is approved, then 8 m must also be approved assuming a center support. But it is not! It apparently has purely mechanical reasons, how forces spread in a beam.
It is standard with cross-bracing in Vårgårdahus floor structures anyway. I didn't find it too terribly hard to do. But I can't claim that I chuckled contentedly while doing it either...
Possible, but the industry's designers are at least in agreement...