ᐅ Forgot to insulate the dormer wall – mold on the wood – what should I do?
Created on: 16 Dec 2022 10:44
F
Fipsi.ch
Hello everyone,
We are building our house with a developer. Currently, we are in the process of drying the screed, and the heating program is running.
During the roof insulation (early October), the responsible company forgot to install insulation and a vapor barrier on the dormer wall. As a result, mold has developed on the exposed wooden dormer wall. This likely happened because this wall faces the outside and is made only of wood and metal – so cold plus moisture equals mold.
This wood is still somewhat damp (like the rest of the house, since we are still in the drying phase) and repeatedly shows fuzzy mold spots. At first, the developer wanted to hold us responsible for this, as we are in charge of ventilation and heating. However, since he did not fulfill his role as site manager, the insulation was simply forgotten. Therefore, we see him as responsible. From what I understand, he agrees with this.
Yesterday, he called the interior finishing company to the construction site so they could install the missing insulation and vapor barrier. I sent these workers away again because I believe this wood first needs to be cleaned from mold. Additionally, I wasn’t sure whether they were merely informed about the missing insulation or if they had been directly tasked with the installation.
I have already treated the wood with mold cleaner, but unfortunately, some fuzzy spots have reappeared. The developer believes that the wood can still dry under the insulation and that this is not a problem. Is the developer’s approach correct?
I am concerned that this could spread the mold into the insulation, causing it to slowly rot. The wood might dry out eventually, but the mold contamination would still be there. I would appreciate a few experienced opinions, thank you!
We are building our house with a developer. Currently, we are in the process of drying the screed, and the heating program is running.
During the roof insulation (early October), the responsible company forgot to install insulation and a vapor barrier on the dormer wall. As a result, mold has developed on the exposed wooden dormer wall. This likely happened because this wall faces the outside and is made only of wood and metal – so cold plus moisture equals mold.
This wood is still somewhat damp (like the rest of the house, since we are still in the drying phase) and repeatedly shows fuzzy mold spots. At first, the developer wanted to hold us responsible for this, as we are in charge of ventilation and heating. However, since he did not fulfill his role as site manager, the insulation was simply forgotten. Therefore, we see him as responsible. From what I understand, he agrees with this.
Yesterday, he called the interior finishing company to the construction site so they could install the missing insulation and vapor barrier. I sent these workers away again because I believe this wood first needs to be cleaned from mold. Additionally, I wasn’t sure whether they were merely informed about the missing insulation or if they had been directly tasked with the installation.
I have already treated the wood with mold cleaner, but unfortunately, some fuzzy spots have reappeared. The developer believes that the wood can still dry under the insulation and that this is not a problem. Is the developer’s approach correct?
I am concerned that this could spread the mold into the insulation, causing it to slowly rot. The wood might dry out eventually, but the mold contamination would still be there. I would appreciate a few experienced opinions, thank you!
W
WilderSueden16 Dec 2022 11:29Fipsi.ch schrieb:
There is no independent construction supervision.You really should change that. The site manager is an employee of the contractor, so there is a conflict of interest. In this specific case, he should have acted because the conflict would have been immediately obvious. I would therefore assume negligence on the part of the site manager. And that is exactly why you want an expert who represents only your own interests.Our contract clearly states that our general contractor (GC) is also responsible for site management, including supervising the quality of the various trades and intervening if necessary.
I understand that there is a conflict of interest, and we may consider bringing in an independent expert if needed.
However, that is not the main issue here.
I would like to know the best way to deal with this moldy wall now.
Option A: Treat the wood (mold remover or similar) and let it dry, then install the insulation plus vapor barrier
Option B: Treat the wood (mold remover or similar) and immediately install the insulation plus vapor barrier
Or perhaps there is a completely different alternative.
I understand that there is a conflict of interest, and we may consider bringing in an independent expert if needed.
However, that is not the main issue here.
I would like to know the best way to deal with this moldy wall now.
Option A: Treat the wood (mold remover or similar) and let it dry, then install the insulation plus vapor barrier
Option B: Treat the wood (mold remover or similar) and immediately install the insulation plus vapor barrier
Or perhaps there is a completely different alternative.
I feel like we are talking past each other 😀
The general contractor sent workers to the construction site yesterday. They were supposed to install insulation and a vapor barrier. As a layperson, I consider this risky, which is why I sent the workers away again yesterday. The general contractor did not inform us about this measure, and the workers did not oppose my reasoning for rejecting it.
It is important for me to know how to resolve this issue professionally. I would prefer not to be held responsible later if technically correct solutions could not be completed on time.
At the moment, I am not concerned about responsibility or anything like that, but genuinely seeking a professionally informed opinion on how to proceed.
The general contractor sent workers to the construction site yesterday. They were supposed to install insulation and a vapor barrier. As a layperson, I consider this risky, which is why I sent the workers away again yesterday. The general contractor did not inform us about this measure, and the workers did not oppose my reasoning for rejecting it.
It is important for me to know how to resolve this issue professionally. I would prefer not to be held responsible later if technically correct solutions could not be completed on time.
At the moment, I am not concerned about responsibility or anything like that, but genuinely seeking a professionally informed opinion on how to proceed.
Fipsi.ch schrieb:
Option A: Treat the wood (mold cleaner or similar) and let it dry, then install the insulation plus vapor barrier
Option B: Treat the wood (mold cleaner or similar) and immediately install the insulation plus vapor barrier
Or maybe there is a completely different alternative. The current "problem" is that during screed drying, you have warm, moist air inside the house, and at the current outside temperatures around 0°C (32°F), this immediately causes condensation on the wood panel/exterior wall. Without additional measures, you won’t be able to dry it.
In any case: First remove the mold and, for example, apply a lime wash to temporarily stop growth. Then…
Option A: Set up an electric fan heater blowing warm air towards the dormer/dormer wall and run it for one day. Then the dormer wall will be sufficiently dry, because the warm airflow prevents condensation and dries out the panel. Immediately afterwards, install the insulation and vapor retarder on the interior side and seal it airtight!
Make sure the fan heater is electric; do not use a gas heater, as it produces warm, moist air from combustion gases.
Option B: Insulate the still damp panel from the inside right away and seal it as in Option A. The panel will still be moist, but no more moisture will come in, and over time the panel will dry out. This should also work, but how quickly depends on the ventilation behind the metal cladding. Probably almost none, so it may take until spring.
I would try to convince the general contractor to go with Option A or at least ask them to present their plan for resolving this issue. If their plan only includes installing the insulation, I would push for Option A.
Later, the mold will actually be harmless, even if some spores remain on the wood. As long as the wood no longer gets wet, the mold won’t continue growing, and the spores are outside the living space. Given the likely affected area, this is not critical.
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