hahaha Trust me, I handle such things almost daily and there are no problems at all with a normal car, the trusses are hardly longer than the car and not wider either.Gabbe1 said:
80 kg is nothing remarkable to carry around either? 4 cement bags are standard for builders to carry with them and that's 100 kg.
Well, it's not a theory but basic structural mechanics and physics. I didn't mean that one should just race around with it on a public road. I primarily meant those last few kilometers to the house that can be tricky for a full-sized truck...Micke_vb said:Hehe... Try convincing Harry Haffa about that theory....
80 kilos is a lot to "carry around" alone, yes. You might manage to move such a truss a few meters, but to lift it up and align it on a build, and additionally handle 7 others the same way, you'd probably need at least 3 people.Tossegubbe said:
Furthermore, I find it hard to believe that 80 kilos is enough; my 4.5-meter trusses for the garage without an upper floor weighed 43 kilos each, factory-made, and the guy wants 7 meters with an upper floor.
Vehicle load limits are not recommendations; they are fixed limits that should be followed even when the vehicle is stationary. It's not about highway speeds, it's about structural integrity. Overloading the roof can easily lead to severe structural damage to the vehicle, and loading up to a ton in or on a vehicle likely leads to the death of the vehicle and driver.
A 7-meter span plus foot length results in a truss up to 8 meters, on a car roof that's roughly 2 meters, which is just about 6 meters or 300% longer than the loading area, so yes, it's quite a bit larger.
Yes, it depends on the person carrying, of course, but several of the guys here at the office can easily take 80kg in each hand and walk 20-30m, so needing three people to lift one end of an 80kg chair? But as I interpret it, the chairs are to sit on top of an upper floor, not to serve as an upper floor themselves. That is, a regular truss without reinforcements, etc. Then they don't normally exceed 80kg.
"The load weight of cars is not a recommendation, it is a set limit that must be followed even when the car is stationary, it's not about highway speed, it's about structural integrity. Overloading the roof can easily lead to serious damage to the car's structure, and loading up to a ton in or on a car will likely lead to the car's and driver's demise."
But how do you reason here? Isn't it obvious that there is a difference (an enormously big one) in the structural load on a car if you have 100kg on the roof at 140km/h and hit a bump or curve, plus a not insignificant wind load compared to when you're standing still? Moreover, manufacturers don't make calculations that are on the margin but more likely with at least 3-4 times safety margins because people generally don't drive sensibly.
When I worked for a period in automotive engineering and developed tow trucks, we calculated precisely such things, and in one example, I can mention that an axle needed to be 80% stronger if it was to handle 80km/h instead of 60km/h and still be within the manufacturer's tolerances.
I also want to point out that I'm not recommending anyone load 1000kg on an ordinary roof rack (even if it holds unless it's from Biltema), but this was now about a maximum of 5x80kg, i.e., 400kg, which I have loaded several times on a small Golf 1 from '82 when we drove the bridges down to the lake, and if a car like that can manage it, it would be nothing short of scandalous if a modern V70, for example, couldn't handle it without issues?
"The load weight of cars is not a recommendation, it is a set limit that must be followed even when the car is stationary, it's not about highway speed, it's about structural integrity. Overloading the roof can easily lead to serious damage to the car's structure, and loading up to a ton in or on a car will likely lead to the car's and driver's demise."
But how do you reason here? Isn't it obvious that there is a difference (an enormously big one) in the structural load on a car if you have 100kg on the roof at 140km/h and hit a bump or curve, plus a not insignificant wind load compared to when you're standing still? Moreover, manufacturers don't make calculations that are on the margin but more likely with at least 3-4 times safety margins because people generally don't drive sensibly.
When I worked for a period in automotive engineering and developed tow trucks, we calculated precisely such things, and in one example, I can mention that an axle needed to be 80% stronger if it was to handle 80km/h instead of 60km/h and still be within the manufacturer's tolerances.
I also want to point out that I'm not recommending anyone load 1000kg on an ordinary roof rack (even if it holds unless it's from Biltema), but this was now about a maximum of 5x80kg, i.e., 400kg, which I have loaded several times on a small Golf 1 from '82 when we drove the bridges down to the lake, and if a car like that can manage it, it would be nothing short of scandalous if a modern V70, for example, couldn't handle it without issues?
Depends on the car Pagno, I was allowed 250kg on the Landrover but here we weren't talking legally but suitably and possibly
Just wanted to say that the roof trusses are for the upper floor (attic) on the second floor. So they need to be lifted about 3 meters from the ground.
I'm not quite sure how to do it practically, I was thinking of building a scaffold around... it will probably be in the way when it's time to lift? Also, I suppose I need to refrain from mounting one of the walls before the trusses are up?
I'm not quite sure how to do it practically, I was thinking of building a scaffold around... it will probably be in the way when it's time to lift? Also, I suppose I need to refrain from mounting one of the walls before the trusses are up?
If you set them up on the tip on the ground below and lean them up, then more than half is already up, just tip them up then..
About 3 people are probably needed, as mentioned, to get them up, you need to lift one side first, then lift the other side while climbing a ladder.
Do you mean or do you not mean that you should have the upper floor in the roof truss?
Do you mean or do you not mean that you should have the upper floor in the roof truss?
When I built an extension this summer, 9 W-trusses were lifted onto the wall plate 5 meters above the ground. The trusses were made of 45x170 lumber and weighed about 70-80kg each. We were 4 men, it probably could have been done with 3 as well, but if we had been two, it likely would have ended with injuries to either us or the trusses.
Regarding transportation, it is out of the question to transport such a truss on a car roof. They cannot lie on a 1.5x2m surface without being damaged by their own weight. They should always be transported standing; when/if they lie down, they must have multiple support points.
Regarding transportation, it is out of the question to transport such a truss on a car roof. They cannot lie on a 1.5x2m surface without being damaged by their own weight. They should always be transported standing; when/if they lie down, they must have multiple support points.