Maybe you could try closing all interior doors for a few days to see if you can help identify the location of the source, If possible without air handlers running. Like others have said something is still hiding, I like the microscope idea, the sooner you can rule things out the closer you get to the answer.
If you can you post some pictures of the house including basement and attic maybe someone will see something that was overlooked.
we have looked at the dust samples and a sample of cellulose insulation under a microscope at our local health dept. they did look the same. I am 99% sure this is our enemy. i just need help identifying the source of entry and the cure.
david graciously did diagnostics back in june and gave us a list of recommendations. we have gone to quite extreme measures to address these recommendations, but still have the dust problem, so although we have improved considerably on our home, we still must be missing the particular problem that is allowing the insulation dust into the living space.
i have trialed days without HVAC, days without clothes drier, clean just before bed and by AM (with no activity or opening of doors, etc. in the home) there is enough dust to suggest the house has not been cleaned in a month...I can literally rake up a pile of dust on the floors or countertops with my hands after only 8 hours! This is not OCD, it is unhealthy living conditions.
i am begging for help on what to do next, specifically how to do it, and then I'll probably need help on how to correct any further identified problems. We simply don't have any building science experts in our immediate area and it is quite challenging for me to manage a household, raise 3 preschoolers, and hold down my day job while trying for a year now to solve construction problems that I have no expertise in.
fireplace.....this is an area I am focusing on now. we have two direct vent fireplaces. one has a glass enclosure and no chimney, just direct vent out the wall. the other has an open front (can be converted to wood-burning) and has a pipe running out of the firebox through a very tall stone-faced chimney. we have found we have air movement into the home through the chimney (not the firebox/piping, but the space surrounding the firebox). The chimney exits the house through a cathedral ceiling, though, and does not pass through the attic where the blown insulation is. I have not been able to figure out if/how there might be communication with the cellulose space. I also don't know how this should be sealed to avoid the infiltration.
we do keep doors closed at times, but we have a lot of air movement and despite changing variables from time to time, find that the dust gets into all rooms. i really don't think it is the supply vents as they are so clean, but it is difficult to keep areas isolated with a family of five. it has been suggested to use a blacklight at night to try to watch the dust patterns. Would this be doable?
is it possible this is a problem without solution? could something have been done during construction that is not reasonably reparable now? I'm to the point I would sell the house, but I could not ethically pass this problem on to a buyer.
I'm sorry this is such a long post. I just want to provide as much info as I can to allow you experts to brainstorm.
thank you to all of you who are offering constructive advice. i greatly appreciate your assistance!
Originally Posted by leeannwc
You never know, it could be a shady (or careless) contractor who placed insulation in your ducts somewhere down the line where it is inaccessible.
I have to ask.. All your recessed lights are sealed, right?
I don't know how a black light works on dust, but if it does, you can get that along with a professional camera guy to take a video of one nights' worth of duxt settling and play it back in super speed. You may be able to see where the dust is coming from. It seems to be coming down fast enough to catch with the camera on fast speed over an 8 hour period of time with the right lighting. Black light or bright light, not sure which to use. Maybe the pro camera guy could help with that question as well. gl
Have you cleaned/washed your walls and ceilings? I wonder if it's something holding this stuff on your surfaces and letting them go intermittently.
I'm assuming you have a very low Air exchange rate in your home because you've sealed everything.
we have sealed the can lights. they leaked like seives when we first occupied the house. they easily could have been the cause, but after sealing, no improvement. I have cleaned top to bottom ceilings, walls, trim because I too thought originally that it could just be mess from construction gradually falling off. this, too, gave no improvement.
all of our ductwork has been accessible to this investigation. the upstairs is in the attic and we tore out our basement ceiling to reveal what supplies the main floor and basement. although it was very leaky, the contractors found it not to be very dirty and found no communication between the downstairs ductwork and the attic. We did get the sealing done, but no less dust.
It sounds like the hole is pretty big to let that much in, I strongly suggest isolating rooms to give you some direction to look since you have already examined ductwork and done some attic sealing. If isolating an area confines the problem you probably are looking for a bypass in the building, if it doesn't it probably is in the ductwork. Has anyone mentioned a duct leakage test, or ductblaster? Again, some pictures might help. It's too bad whoever did your blower door test was not a little more helpful. They should have been able to identify areas and rooms with more leakage quite easily, the air really rips through them. Were you there for the test? I have seen cases that air was coming from the supply registers during testing, guess what, big leaks from the attic. I know you looked at that too but something is missing.
Good idea about sealing rooms and ruling out that particular area. I still think checking out all air handlers and the unit in the attic. Sometimes these may not be sealed well and unfiltered air is being drawn in and then dispersed throughout the house. Also, did you seal around all bathroom fans?
1.You stated the duct was well sealed – you need a duct blaster test to confirm this. I did a duct test behind an Aeroseal job and found leaks.
2. Did you remove the return grille and caulk/foam the area? I have seen many large openings behind the grill base that are open to the attic.
3. Combustion air vents – do they discharge in attic?
4. In order to solve a problem like this you need to understand pressures in the house. What was the baseline pressure with respect to outside for the blower door test? You also need a room-by-room evaluation to determine the pressures in the house both with doors open and closed.
5. You also need to get the pressure of the inside with respect to the attic. Then check it with the A/H on, then the dryer, then with doors closed, etc.
6. I would hook up a temporary exhaust fan in the attic, discharging to the outside, to make sure the attic stays negative with respect to the inside. This should eliminate the attic insulation as a source, or prove that it is the problem.
7. What type of insulation is in the walls?
8. Air handler sealing - was this done?
9. Supply vs. return flows? Does an imbalance exist?
10. Another test would be using a theatrical fog machine. Use it with the ducts and also in the attic. Fog in the attic with a blower door drawing a negative pressure in the house may give you some clues. I would not do this until the pressures are determined.
11. In all cases make sure the gas appliances are safely secured prior to operating blowers.
Last edited by dcmcm5; 10-08-2007 at 10:05 PM.
leeannwc - I'm trying to solve a similar dust problem and wondered if you have solved this one?
You have to identify what it is that is blowing around in your house. I would suspect the blown in attic insulation since you say fiberous material. was the attic duct installed before or after the blown in insulation?Could it be that when installing duct that some of this materiel was accidently sucked into the supply flex. Is one room more dusty then the others? is this materiel on the filter? If you dont identify what the dust is you will never fix the problem complete. AS others suggested ADD FRESH air to the house.
Guess I'll try a few suggestions too.
I see where you compared the dust with attic insulation....
but I just wanted to throw this out there just in case.
Make sure your dryer vent is vented correctly.
Needs to terminate outside (I find way too many that blow under houses)
If it does vent to outside, check to see how pipe connects to last peice mounted to wall.... it should NOT look like this
I find a lot of dryers that are not hooked up to the vent pipe very well also.
(the very first connection to the dryer)
dcmcm5--sorry such a late response. i thought i'd gotten all the responses i was going to and quit checking in. No, I have not solved the problem and am now almost suicidal. i appreciate all your suggestions, but most of them are beyond my expertise/resources. here's what i have in response to your questions:
1)the only person i can find with a ductblaster is the aeroseal contractor and i'm not sure he is reputable. i have been trying to check him out.
2)i have removed all return grills and caulked between the boots and drywall/flooring. we also had an hvac contractor seal the boots from the attic side.
3)nothing vents to the attic...all is to the outside
4/5)the blower door test was done by the RECC but from what i gather on this forum not a very thorough job. i have not even been able to get written results from them, only that the infiltrations were "within normal limits". i don't know where else to turn to measure pressures and frankly don't have any more money to spend without confidence that the procedures are going to lead to a solution. we have already spent $10,000 trying to solve this problem (not to mention endless hours of my own time away from my kids).
6)we do have an exhaust fan in the attic although i have never known it to kick on. i will have to investigate how to get it running. we have 2 large gable vents in the attic that move A LOT of air. it is always breezy up there. I guess this could help rule-in an infiltration/bypass if the problem resolved with the attic under negative pressure.
7)batting in walls, but i'm not convinced that there are not leaking top plates allowing air and cellulose to travel the walls
8)i was told by the hvac contractor who repaired our ductwork that they checked the handlers for leakage/bypass as well
9)there was an imbalance between supply and return airflows prior to our repair work, but there has not been any post-testing
10)not something i am capable of conducting myself and again have found no resources in my area to do anything like this or pressure testing
thank you for your suggestions. if you find any answers while addressing your own problem, please share. If I find relief I will be sure to notify everyone!
wormy...drier vent checked thoroughly and in addition have trialed days without laundry with no change in dust levels.
Where are you located? I may know someone that can help.
You can also look here http://www.resnet.us/directory/raters.aspx for a rater near you. They will all have blower doors and duct blasters, and will know how to use them correctly. They should also be able to do tests on the house to determine what rooms are positive/negative.
As for the fan you have in the attic, it needs to be one that draws from the attic and not the house. I was thinking any type of small fan that you could hook a section of flexible duct or pipe to the discharge and run to an outside vent. This takes the attic negative with respect to the house and eliminates potential infiltration.
While I generally like Aeroseal, I would hold off before spending that much money. The house that I am working on was sealed by an aeroseal contractor and it still has dust.
I am in central KY. I searched the resnet directory you provided and one of those contractors in Lexington I had already contacted today to see if they could help. I have not yet heard back from them. My days off work are spent like this: I send my kids to daycare so they can breathe and I can...CLEAN...research on the internet/make contacts....experimental fixes of my own...repeat....for over a year now! I most resent that I am missing their childhood sending them off each day, but I don't know how we'll ever move past this if I don't stay on it. There are a few on this forum who have helped me (THANK YOU), and have done some diagnostic work for me, but they are a few hours away and have not yet been able to make another home visit. They are currently trying to track down a thermal imager to look for bypasses/infiltrations before they invest their time and energy making the trip. That piece of equipment is proving quite challenging to locate, though. I really appreciate everyone's help. We can't fix this problem soon enough. I feel like my family is dying in here.