ᐅ OSB Boards for the Attic "Required," Yet Additional Charges?
Created on: 19 May 2016 14:56
T
tlactar
Hello,
we have recently started building (or rather having it built). Turnkey with an “all-inclusive price.”
Yesterday, the construction company called me and said: “We would now lift the OSB boards for the attic floor up to the roof structure for you. The boards cost about €580 for 40m² (430 ft²), and whether you install them yourself or not (980€ / about $1,080) is up to you.” ... okay? When I replied that I could get them significantly cheaper if I bought them myself, they said: “Alright, but these boards are included in the structural calculations, so please install them promptly.” ... o...k?
Now the question: is it really true that these boards are necessary? It seems odd to me... and if they are, shouldn’t they be included in the price? We had repeatedly asked beforehand if there might be any additional costs, but this was never mentioned. Is this even legal? Would they build us a structurally insufficient house without these boards?
we have recently started building (or rather having it built). Turnkey with an “all-inclusive price.”
Yesterday, the construction company called me and said: “We would now lift the OSB boards for the attic floor up to the roof structure for you. The boards cost about €580 for 40m² (430 ft²), and whether you install them yourself or not (980€ / about $1,080) is up to you.” ... okay? When I replied that I could get them significantly cheaper if I bought them myself, they said: “Alright, but these boards are included in the structural calculations, so please install them promptly.” ... o...k?
Now the question: is it really true that these boards are necessary? It seems odd to me... and if they are, shouldn’t they be included in the price? We had repeatedly asked beforehand if there might be any additional costs, but this was never mentioned. Is this even legal? Would they build us a structurally insufficient house without these boards?
Unfortunately, there isn’t much left; it is a one-and-a-half-story building. But that’s not too bad since there is also a basement.
According to an email, they want to send me the structural calculations separately. If it really states that they are necessary, I will follow the advice and insist that this is included in the price.
Bringing the materials up nevertheless is a bit tricky; they kindly only thought of it at the last minute. The roof structure is planned to be finished today, then it will be closed up.
Sure, a few hundred dollars don’t make a big difference, but on the one hand, I find the approach a bit unfair in principle, and on the other hand, these “unforeseen” additional costs unfortunately add up.
According to an email, they want to send me the structural calculations separately. If it really states that they are necessary, I will follow the advice and insist that this is included in the price.
Bringing the materials up nevertheless is a bit tricky; they kindly only thought of it at the last minute. The roof structure is planned to be finished today, then it will be closed up.
Sure, a few hundred dollars don’t make a big difference, but on the one hand, I find the approach a bit unfair in principle, and on the other hand, these “unforeseen” additional costs unfortunately add up.
For us, the 22 mm OSB panels for about 100 sqm (1,076 sq ft) cost approximately 850 euros including VAT – so that was an additional expense.
Considering that I didn’t have to buy, transport (without a tow hitch or a small van/truck), and especially lift the panels by myself, I found the price reasonable. But for you, it’s definitely a bigger deal. By the way, on the general contractor’s advice, we bought the panels directly through the carpentry company. They brought them along with the roof structure.
Regarding the comment about the structural engineering, I can’t make sense of it. Maybe our moderators @wpic and @Bauexperte can provide some additional information.
Another point also raises some doubts for me. Our general contractor specifically advised us not to install the OSB panels immediately, since the house was still drying out (which carries a higher risk of mold growth). We were told to wait about one year, which we faithfully did. This advice has been discussed in this forum before and seems to be quite common.
Considering that I didn’t have to buy, transport (without a tow hitch or a small van/truck), and especially lift the panels by myself, I found the price reasonable. But for you, it’s definitely a bigger deal. By the way, on the general contractor’s advice, we bought the panels directly through the carpentry company. They brought them along with the roof structure.
Regarding the comment about the structural engineering, I can’t make sense of it. Maybe our moderators @wpic and @Bauexperte can provide some additional information.
Another point also raises some doubts for me. Our general contractor specifically advised us not to install the OSB panels immediately, since the house was still drying out (which carries a higher risk of mold growth). We were told to wait about one year, which we faithfully did. This advice has been discussed in this forum before and seems to be quite common.
f-pNo schrieb:
Another point also makes me cautious. Our general contractor specifically advised us not to install our OSB boards immediately because the house is still drying out (there is a higher risk of mold growth). We were told to wait about 1 year, which we have strictly followed. This advice has been discussed in this forum before and seems to be common practice. This advice should definitely be followed. During our first winter, we had a slight mold issue on the attic ceiling. It was due to residual moisture, since no new moisture was entering, the attic is ventilated, and I couldn’t detect anything with a thermal imaging camera.
The residual moisture in new builds is considerable, even if a ventilation system might suggest otherwise.
Musketier schrieb:
We deliberately installed tongue and groove boards instead of OSB panels. OSB acts as a vapor barrier.I’ve read that in the mentioned thread as well. However, back then, the panels were already installed, and the house still had a year to dry out. Additionally, we left a gap of about 15–20 cm (6–8 inches) all around and made the panel cutouts around the load-bearing support beams slightly larger. This way, the attic is not completely sealed.
So far, in the last six months (since installation), we have noticed no issues in this regard.
Payday schrieb:
ps: OSB panels require cross battens underneath to allow air circulation.As already mentioned on page 1: OSB panels need cross battens underneath so that air can circulate. After drying for one year, OSB is not a problem. Once the attic is dry and properly ventilated (using wedges between the overlapping membranes), no issues can occur. If the house’s true vapor barrier (located beneath the insulation when viewed from above) is airtight, no moisture can enter the attic.
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