Hi, I want to build an additional floor over half of the living space of our single-story Elementhus from '59. The plan is for finished wall and roof modules to be lifted into place. Metal roof instead of tiles and self-supporting roof trusses, meaning a lighter roof than today and still no heavy ridge beam that needs to be unloaded. Will the existing walls on the lower floor hold? Or do both exterior and interior walls there need to be reinforced with pillars, for example, opening up the wall elements and inserting VKR pillars resting on the foundation wall/chimney stacks (crawl space)? There are differing opinions among the contractors I've consulted. I want to minimize unnecessary hassle.
Hello and welcome to the Byggahus forum!
I interpret your post as wanting to go from a 1-story to a 2-story building (i.e., not 1 1/2-story). There shouldn't be any problem determining what loads your Mockfjärd elements can handle. What's primarily added are the floor loads from the second floor. The roof loads are just moved one story up, and the walls don't weigh much. Regarding the roof loads, they mainly consist of snow loads, which vary depending on where you live. In relation to the snow load, the difference between metal and tile is usually negligible. As for the roof construction, I have the opposite opinion. A ridge beam (if its support pillars can be brought down to a suitable point) takes half of the roof load, which reduces the load on the exterior walls to half compared to a normal truss.
If you want more opinions, you'll probably need to upload some drawings of the existing house, at least plan and section.
I interpret your post as wanting to go from a 1-story to a 2-story building (i.e., not 1 1/2-story). There shouldn't be any problem determining what loads your Mockfjärd elements can handle. What's primarily added are the floor loads from the second floor. The roof loads are just moved one story up, and the walls don't weigh much. Regarding the roof loads, they mainly consist of snow loads, which vary depending on where you live. In relation to the snow load, the difference between metal and tile is usually negligible. As for the roof construction, I have the opposite opinion. A ridge beam (if its support pillars can be brought down to a suitable point) takes half of the roof load, which reduces the load on the exterior walls to half compared to a normal truss.
If you want more opinions, you'll probably need to upload some drawings of the existing house, at least plan and section.
Hello and thanks for the quick response! Yes, it will be 2-story. A new floor structure that can support the addition must be installed on the second floor, as there is none today. I was hoping someone on the forum who has built onto their 1-story Elementhus without load-bearing posts down to the foundation could share if the house has held up as it should. We do have two standing layers with 20 mm = 40 mm cross-laminated wood + high-pressure wood shavings in each element that are connected along the entire wall length... And I also guess that the downward loads are better distributed along the entire foundation without posts. Since the interior walls on the first floor stand on top of the floor elements, the floor might also be tricky to penetrate with posts. As you can see, I would prefer to avoid posts if possible. But: regardless of whether anyone reaches out here or not, I will definitely follow your advice to have an objective expert investigate what loads the elements can withstand before moving forward!