Trusses that are sagging

[FreddruS]

I am a structural engineer myself and agree with justusandersson. I believe they are incorrectly installed with the nail plate in the middle, which is also poorly nailed. From what can be seen in the first image, even some of the nails are too close to the joint between the studs.

 

[bossespecial]

To facilitate for the thread creator, I can also add that I am a designer and believe that justus's suggestion is the right way to go

 

[Pagno]

To facilitate for the thread creator, I can also add that I am a designer and believe that justus's suggestion is the right way to go

What is it in the garage, perhaps a lighter solution can be made?

If I may be allowed to contribute an alternative way, I would have chosen to partially solve the problem from the garage. Are there obstacles to moving in the span with angles in the roof, 500mm from both sides under the rafters does an incredible amount for the load-bearing capacity of the attic.
Just a small thought.

Best regards, P-A

 

[M@ZE]

What is in the garage, could one perhaps make an easier solution?

If I may participate and suggest an alternative way, I would choose to solve the problem partially from the garage. Are there any obstacles to moving the span with angles in the ceiling, 500mm from both directions under the rafters does incredibly much for the load-bearing capacity of the attic.
Just a small thought.

Regards P-A

Right now I'm insulating, using Plyfa and plastering the walls. There's not much in the garage at the moment, just the family's bikes and some wardrobes. Unfortunately, I'm not competent enough to assess your suggestion, P-A, but I appreciate everyone's involvement, it's so incredibly helpful to receive this assistance.

 

[M@ZE]

I realize that placing a Glulam beam 56x225 between each Rafter seems to be what you designers simply recommend.

What I'm wondering is whether they can even be rotated into place in the sections where it is plasted, battened, and screwed with drywall + garage motor/door. It feels like they will hit the supports when trying to rotate them into their respective sections

And is it possible to lift these into place considering their weight?

 

[Pagno]

I realize that placing a Glulam beam 56x225 between each Rafter seems to be what you engineers simply recommend.

What I'm pondering is whether they can even be rotated into place in those sections where it is wrapped in plastic, battened, and screwed gypsum + garage motor/door. It feels like they will hit the supporting legs when you try to rotate them into their respective sections

And can you lift these into place considering their weight?

It will be a problem to rotate, tilt them into place.

I'll make another attempt with my suggestion, if you think of braces, under the rafters, under the horizontal beam, under the floor, against the stud that should sit vertically under the rafter, in the garage wall.

If you make a sandwich wedge, brace, beam shoe, that goes down the wall one meter and half a meter onto the roof, under the roof in the garage, you reduce the span to just over five meters.

If you have propped up the roof in the garage, prop up the outer roof before you put up the "support legs," I would have divided the attic into different sections, set thin screw studs vertically inside the rafters, and screwed plywood from both sides. In other words, completely clad certain rafters as walls.
If you do it this way, you need to plan more about what you will use the space for.
The air will have difficulty circulating, harder to get light via the gable windows, more difficult to move larger materials.
Door openings need to be planned and framed correctly.
Every method brings challenges or difficulties.

Best regards, P-A

 

[justusandersson]

A 6 m long 56x225 weighs about 38 kg. If you insert them diagonally into the compartment, it should work.

 

[bossespecial]

I won't comment on whether glulam is suitable, but the right approach is to build a new floor structure. What largely determines the dimension and material, I would guess, is the deflection. If you accept a potentially large and visible deflection, this is an important factor in determining the dimension. However, there should be some limitation as it can cause problems at the supports (the beam "pulls" at the support when it bends down). Getting the beams in place is somewhat cumbersome but not difficult; I recently did something similar at home.

 

[M@ZE]

I can't comment specifically on whether glulam is suitable, but the idea of building a new floor structure is the right approach. What largely determines the dimension and material, I would guess, is the deflection. If you accept a potentially large and visible deflection, this is an important factor in determining the dimension. However, some limitations should be considered as it can cause issues with the supports (the "rule" pulls on the support when it bends down). Getting the beams in place is a bit cumbersome but not difficult, I have just done something similar at home.

I would probably say that I would prefer not to have any visible deflection (that can be seen with the naked eye). Glulam definitely sounds like a stronger solution but I don't know much about how much it bends, etc., which you seem to know . I saw that Fredells charges 748:- for 6m 56x225 and I might get 10% off too. Of course, this extra cost is a bit unfortunate but it's just something to accept.

I've been trying to find what type of flooring I should screw on when it's cc 120

Ok, so you think they can be maneuvered into place even though I only have 2 slots where it's completely open to the garage, while the rest are covered (unless I need to remove all the plaster, battens, and plastic).

 

[justusandersson]

I have tried to find what type of floor I should screw on when it is cc 120

As bossespecial writes, you determine yourself how much it can flex. Personally, I find it unpleasant with too much flex on a floor. On my garage loft floor, I have tongue-and-groove floorboards that are slightly thicker than usual, about 36 mm, and it works excellently. They were also included in the actual building kit. Tongue-and-groove boards are also much easier to lay in such a space than various types of sheet material.

 

[M@ZE]

It's like bossespecial writes, you decide yourself how much it can flex. Personally, I find it unpleasant with too much flex on a floor. On my garage loft floor, I have tongue-and-groove floorboards that are slightly thicker than usual, about 36 mm, and it works excellently. They were included in the actual building kit. Tongue-and-groove boards are also much easier to lay in such a space than various types of sheet materials.

I completely agree, I don't want too much flex in the floor either, a little is okay but. 36mm tongue-and-groove boards sound expensive haven't found any but maybe I'm looking in the wrong category.

 

[justusandersson]

Mine were not expensive at all. I bought a bit more. You don't need floor quality but slightly better than råspont in pine is sufficient. Check out sawmills nearby.

 

[M@ZE]

Mina var inte alls dyra. Jag köpte till lite. Du behöver inte ha golvkvalitet utan snäppet bättre än råspont i gran räcker. Kolla på sågar i närheten.

Mina var inte alls dyra. Jag köpte till lite. Du behöver inte ha golvkvalitet utan snäppet bättre än råspont i gran räcker. Kolla på sågar i närheten.

Where did you buy yours?

One question, since I have my attic ladder which is 68mm, should I place the glulam beam on that cc measurement instead in one of the sections, or it can be placed lengthwise as well which would actually suit me better but then it takes up 113cm. The alternative was to switch it to a 54cm but I would preferably keep the wide one.

 

[justusandersson]

You can call Mellbygarage in Stora Mellby located in Västergötland. They probably sell all over the country and if not, they can give you tips.

 

[justusandersson]

It is possible to switch out the glulam and the lower frames of the trusses so that you can have the hatch in the garage's longitudinal direction, but it is quite an undertaking. I will try to look into it a little later.