As far as I can see, it's a regular truss (statically determined) and not a scissor truss.
A scissor truss has the bottom chord at a shallower slope than the roof pitch and goes up to meet the opposite side's top chord on the other side of the ridge. This forms a joint where it meets the bottom chord from the other side, which also goes up to the top chord on the opposite side of the ridge. Hence the name scissor truss.
Why this company has adopted the designation scissor truss for a truss, I don't know. Obviously, the namer has poor knowledge of truss design typology.
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Byggaren
A scissor truss has the bottom chord at a shallower slope than the roof pitch and goes up to meet the opposite side's top chord on the other side of the ridge. This forms a joint where it meets the bottom chord from the other side, which also goes up to the top chord on the opposite side of the ridge. Hence the name scissor truss.
Why this company has adopted the designation scissor truss for a truss, I don't know. Obviously, the namer has poor knowledge of truss design typology.
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Byggaren
Ok, it seems to be quite established to call them that:
Takstolsfabriken, Gotland
Saxtakstol. AB VimmerbyHus
Offertförfrågan - Carlenskogs.se
Takstolsfabriken i Sjöbo - Takstolar - Saxtakstol
I think it's safest to call them what the roof truss factories seem to do, that probably minimizes any misunderstandings.
but then maybe the program can handle these roof trusses then?
Takstolsfabriken, Gotland
Saxtakstol. AB VimmerbyHus
Offertförfrågan - Carlenskogs.se
Takstolsfabriken i Sjöbo - Takstolar - Saxtakstol
I think it's safest to call them what the roof truss factories seem to do, that probably minimizes any misunderstandings.
but then maybe the program can handle these roof trusses then?
Not the ones in the Takstolshandboken at least.
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Byggaren
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Byggaren
Can't you draw a scissors truss so everyone understands the difference then?imported_Byggaren said:
Okay. Will attempt to get along with the drawing program in Word and this forum. Complain if nothing is visible 
View attachment Saxtakstol.doc
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Byggaren
View attachment Saxtakstol.doc
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Byggaren
Or maybe it's the roof truss manufacturers who need to learn what a saxtakstol is (see above) and call theirs saxtakstol with statically determined framework to be correct.Snailman said:
But the Gotlänningar should probably be careful with that too. It is not okay according to the requirement that a statically determined framework must meet the rule: 2k=3+s or s=2k-3, where k is the number of joints and s the number of bars in the framework. They have a joint in the bottom frame directly beneath the ridge that does not meet that requirement. Thus, no closed triangle at the top, which it should be to achieve interaction and stability. That joint instead functions as a hinge, larger model, and you can calculate what happens if you press downwards on the ridge with a finger and the eaves slide outward. (The joint gets a torsional moment as the tensile forces don't act in a straight line and aren't countered by any connecting bars.)
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Byggaren
A small reflection, partly OT: interesting that truss suppliers have such good opportunities for customers to get quotes directly via the Internet. Why don't suppliers of regular building materials offer these opportunities? After all, a truss is a much more complicated product than a pile of boards.
Well, say it.
I guess it might have something to do with a lumber supplier also wanting to be paid for their contribution, and then the roof truss manufacturer has to lower the price for the final price to the customer to remain the same. As it stands now, the roof truss manufacturer can take the entire profit margin themselves unless the lumber dealer wants to work for free, that is.
Another explanation could be that since there are relatively few custom builds and all with different specifications and roof designs, it's not profitable for the lumber dealer to invest effort in these.
But you could ask them?
If I were a lumber dealer, I would definitely have provided the service, even if I didn't make any profit from the deal (as long as I didn't lose anything either), provided that the customer committed via a quote to source all their other materials through me.
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The builder
I guess it might have something to do with a lumber supplier also wanting to be paid for their contribution, and then the roof truss manufacturer has to lower the price for the final price to the customer to remain the same. As it stands now, the roof truss manufacturer can take the entire profit margin themselves unless the lumber dealer wants to work for free, that is.
Another explanation could be that since there are relatively few custom builds and all with different specifications and roof designs, it's not profitable for the lumber dealer to invest effort in these.
But you could ask them?
If I were a lumber dealer, I would definitely have provided the service, even if I didn't make any profit from the deal (as long as I didn't lose anything either), provided that the customer committed via a quote to source all their other materials through me.
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The builder
I don't mean that the timber dealers should quote prices on roof trusses but on what they actually sell: studs, plasterboards, insulation, etc. Most dealers don't even have a price list available. And we have noted that it's quite tricky to get a quote at all.
Aha! That was another 5. I misunderstood you.
Yes, indeed. Again a thought/guess.
Previously there was something called the Timber Merchants' Recommended Price List. When you requested a quote, you often received a response that referred to this price list minus X% discount. It no longer exists, as far as I know. Moreover, prices are pressured due to significant competition from building supply stores, and they might not want to reveal their pricing via quotes as they don't know if the inquiry comes from a private individual or someone working there. I would guess that a construction company with a name could get it. I always get it when I request it.
A timber merchant doesn't only sell timber but all building materials, even if it's 'stone'. That is, Leca and lightweight concrete. There the supplier can source from places other than those available in Sweden. (They can do that with timber too, which happens, but our quality requirements for construction timber and the fork stamping can't be imitated, making it easy to see if it's imported or stamped wood from a Swedish sawmill.) Even there, prices are pressured and the same guess applies.
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Builder
Yes, indeed. Again a thought/guess.
Previously there was something called the Timber Merchants' Recommended Price List. When you requested a quote, you often received a response that referred to this price list minus X% discount. It no longer exists, as far as I know. Moreover, prices are pressured due to significant competition from building supply stores, and they might not want to reveal their pricing via quotes as they don't know if the inquiry comes from a private individual or someone working there. I would guess that a construction company with a name could get it. I always get it when I request it.
A timber merchant doesn't only sell timber but all building materials, even if it's 'stone'. That is, Leca and lightweight concrete. There the supplier can source from places other than those available in Sweden. (They can do that with timber too, which happens, but our quality requirements for construction timber and the fork stamping can't be imitated, making it easy to see if it's imported or stamped wood from a Swedish sawmill.) Even there, prices are pressured and the same guess applies.
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Builder
Write the following values: City (snözon), type of roof, span, house length, cc distance, and roof angle, and I will run them in a program I have.
Forgot one more value: eaves length.
This is what I've been looking for. Can you help me calculate mine?sommarbygge said:
City: Karlskrona (Blekinge)
Roof type: Concrete tiles on battens 22mm
Span: 707cm between the outer walls
House length: 770cm
Center-to-center distance: 120 cm
Roof pitch: 14 degrees
Eave length: 40cm
I'm trying to attach a sketch I made in the fine drawing program Excel.
Thank you very much in advance.
Hi BME,
I took the highest wind load value (800), but still need a bit more info. You must choose one of these truss types: Swedish, truss type W or WW, post-supported type 2 or 3-span. There is a fourth type: Framework, but it has 38 or 45 degrees, and you have chosen 14 degrees. Finally, there are 4 quality grades for the wood used in trusses, of which k12 is the weakest, but you must choose, because the dimension is also affected by the wood quality. Check Skogsindustriernas website for wood qualities.
I took the highest wind load value (800), but still need a bit more info. You must choose one of these truss types: Swedish, truss type W or WW, post-supported type 2 or 3-span. There is a fourth type: Framework, but it has 38 or 45 degrees, and you have chosen 14 degrees. Finally, there are 4 quality grades for the wood used in trusses, of which k12 is the weakest, but you must choose, because the dimension is also affected by the wood quality. Check Skogsindustriernas website for wood qualities.
Hello, thank you for your help so far.
I don't know what the different types you mention stand for, but after some browsing, it seems like fackverk will be my answer. Maybe W but I'm not quite sure what that really means. Count on K12.
If you think it should be another way, please feel free to suggest that. My goal, like everyone's, is an easy-to-build, cheap, and safe roof truss.
Best regards, Mattias
I don't know what the different types you mention stand for, but after some browsing, it seems like fackverk will be my answer. Maybe W but I'm not quite sure what that really means. Count on K12.
If you think it should be another way, please feel free to suggest that. My goal, like everyone's, is an easy-to-build, cheap, and safe roof truss.
Best regards, Mattias