Poor attic ventilation, a.k.a. mold on rafters
Here are the basic details:
- I have a 23 year old 2-story frame house in the mid-Atlantic region (Zone 5). The roof was replaced last year, and there is a ridge vent, soffit vents at intervals and baffles inside the attic to allow unimpeded air flow into the attic.
- The bathroom exhaust fans are vented off to side camp vent on the side off the house. Though the fans seem to be running, I have a serious suspicion that they aren't actually pulling in anything.
- The attic space had about R-36 to R-38 of batted and blown in insulation put in by the previous owner and I intended to have someone come by and blow in insulation to bring it up to R-49.
I called in a local contractor to come by & do a full blower audit test and recommend stuff to improve the insulation and recommend other things to improve efficiency. When I went up with him, I noted signs of mold growth in the roof rafters in the attic. There is no sign of water or smell - so it is still in the initial stages.
- Seal penetrations in attic space
- pull back insulation from soffits and reposition baffles to allow air up to the attic to dry out mold.
- Add can light cover to recessed light fixtures
- Build Insulated Attic Hatch w/ Removeable Lid
- I had what seemed like 2 cold air return register in my bedroom: 1 near the ceiling seemed to be NOT connected at all - just vented out straight into the open attic space & the 2nd near the floor that was connected. He suggested removing the vent and drywalling it up.
- Extend bath vent to outside including butterfly air control baffle
1. I agree with all of the recommendations he gives EXCEPT for the last one.
o The mold is on the rafter OPPOSITE the bath exhaust fans on the side that faces the setting sun. There seems to be no mold growth in the rafters right around the bath fans. Is it possible the stronger heat of the setting sun can create mold on the rafter if there is enough moisture in the attic but not in the region of the source of the moisture? If I am right re: the non-working of the fans is this a contributing factor as well?
o The bath vents already are vented outside via the side camp vent. Is there any benefit in going through the roof with a butterfly air control baffle?
2. Can return air registers be near the floor? I thought they needed to be up near the ceiling. My concern is whether the upper register needs proper ducting to do the job right as opposed to drywalling it off and have some other issue crop up.
3. When I look up straight at my ridge vent, I see a blue mesh along the length. Is this normal? The roof replacement was the last change done, so there is good reason to suspect that could be the reason for the poor attic insulation.
I have called 3 insulation guys to comment on these issues. Only 1 did a blower test and recommended the above. The rest were like - not our problem. Call someone else. We just dump insulation The question is who do I call:
- HVAC guy?
- Mold remediation guy?
Please help. I'd appreciate any help, because I'd like to get this taken care of and I have just one guys recommendations & estimate (obviously the highest of the lot) and I am at my wits end.
Posted Wed, 04/23/2014 - 10:24
Edited Wed, 04/23/2014 - 11:18
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