OSB panels for the attic "required", yet extra charge?

Hello,

we have been building for a short time (or having it built). Turnkey with a "fixed price."

Now the construction company called me yesterday and said: "We would now carry the OSB boards for the attic up into the roof structure, the boards cost ~580€ for 40m², and whether you install them yourself or not (980€) you can decide." ... okay? After I said that I could get them much cheaper if I bought them myself, they said: "Alright, but the boards are included in the structural calculation, so please install them promptly"... o.....k?

Now the question: can it really be true that the boards are necessary? Seems strange to me... and if they were - shouldn't they be included in the price? We kept asking beforehand which additional costs might come up - this was never mentioned. Is that legal? Would they build us a structurally insufficient house without those things?

What does your independent expert who is overseeing the construction and has reviewed the contract say?

With your scant information, no one can provide you with qualified help here.

Hi,

OSB boards shouldn't be included, that's quite common. They are not included for us either and neither for all the neighbors I've talked to. 14 € per sqm is definitely on the expensive side, you can get them at OBI between 4 and 8 € depending on the thickness. So if they are not some super special ones, the price is a bit cheeky. I wouldn't bother with buying them myself for 100 €, (= comparing prices, getting a trailer, driving to the hardware store, having it loaded, driving to the construction site at the right time, etc), but for several hundred euros, yes.

The interesting part is the statement that they are required for the statics. Your construction company shot themselves in the foot with that. I would now smile and refer to the contract which surely states that the house will have a correct statics, and then they should pay for it themselves.

As I said, it seems normal that they are not included in the price, but with his statement, the construction company guy actually gave them to you for free.

Best regards,

Andreas

actually quite simple. there is a structural calculation. this will be handed over to you at the latest upon completion anyway (so-called documentation). ask for the structural calculation now and take a look to see if the osb boards are really included.

basically it is even simpler: if they are really required structurally, the construction company owes them to you, since it has contractually guaranteed the proper slope of the roof.

if it is not structurally required, it does not have to be provided.

the question remains how osb boards can play a structural role at all, except that their inclusion results in thicker beams being calculated (higher weight) and thus only benefits the builder.

After I said that I could get them significantly cheaper if I bought them myself, the response was: "Alright, but the panels are included in the static calculations, so please install them promptly"... o.....k?

I think there's a misunderstanding. They are certainly not necessary for the structural integrity of the house/roof truss.

buying (= comparing prices, getting a trailer, driving to the hardware store, having it loaded, driving to the construction site at the right time, etc.) not bothering with that, but spending a few hundred on it is okay.

You forget carrying them up individually

With us, the panels could be purchased along with installation for 1500 euros.

So of course we will do it ourselves. Structural engineering was never mentioned to us.