I have this very bad smell in 2 of my rooms in my house that was built in 2003. The 2 rooms that have the smell have exterior brick veneer. I suspect something to do with the brick veneer. The strange thing is that I go all winter with out the smell, but as soon as it warms up, the smell comes back.

I saw the brick go in when they were building the house, so I know there is flashing at the bottom. The Brick contractor also made sure the carpenter came back to put up tyvek where there was missing tyvek. There are also weep ropes consistently placed along the entire bottom coarse of brick, above the flashing. I see no evidence of leaking in the basement along the rim joist.

Things seem to be constucted correctly, yet I have no idea why I am getting this terrible mildew smell.......if anyone has any other suggestions in regard to what to check, it would be greatly appreciated.

Thanks,
fischler@comcast.net

The smell you have can be from many factors. To understand what is going on you must understand how a mildew odor is created.

Any mildew/mold smell requires three items to develop. A food source, air and moisture. Knowing this and understanding you can only control the moisture side of things we must look at where this moisture is coming from.

Now you suspect the brick veneer is the issue. You say that the contractor put behind the brick Tyvek and that the contractor placed weep holes, and flashings. Is the flashing located at the floor sill level or is it below that point below the surface of the grading? The weep holes are placed on top of this flashing. Is the brick spaced off of the house framing at least 1/2 inch from the wall? Did they clean out behind the brick when they place them? Or did the contractor allow the mortar to squeeze out and come into contact with the Tyvek covered wall?

My thoughts on this even if they did install the walls properly or incorrectly this is not the source of the moisture.

We need some more information. Where are the rooms located within the house. Basement, first floor, 2nd? I assume they are next to the brick veneer side. Which way does the room face? North, south etc?

What kind of heat to you have? AC system installed? Overhead or in walls with air ducts?

Do you have plastic runners, on floors? What about carpets? If you have them does the sun shine onto them through the windows? What about drapes? What are they made of or do you have plastic blinds?

What part of country do you live, USA or other country?

How long has this odor been taking place? Recently or sense the house built? Did it seem to appear after you perhaps changed the look of the rooms in question? What do they have in common. Are they next to each other, or do they just face the same way and are in different locations in the home?

Reason for these questions is that many of the products we fashion our homes with contains many man made chemicals. These chemicals out-gas all types of odors. If the sun shines on some of these materials they can give off smells that mimic mildew and mold.
leaking brick walls which results in moisture and odors would happen pretty much all year round. Moisture does not stop just because its winter out.

Recently there has been some issues with the wallboard that was installed in many of the homes down in the southern states. It appears that due to the hurricane a few years back they ran out of the stuff for construction. They began to import a lot more drywall from China then they did in years past. It appears that this drywall contained some pretty nasty things that have been giving off some strange smells.

If you suspect that your home contains this material I suggest you visit the web site http://chinesedrywallcomplaintcenter.com/ to find out more.

Answer these questions and perhaps I can offer some advice on what way to go.

It would help to know what part of the country you are in or what the temepratures are like when this occurs. You said that you watched the flashing going in during construction. It should have been metal and turned up the exterior of the stud wall a few inches. The tyvek or some sort of weather shield should have run down past the top of it. There should have been provisions to clean out any mortar that fell down in the cavity during construction of the brick veneer. Many times the weeps are blocked by fallen excess mortar that lands at the bottom on the cavity. I've seen rubber used as base flashing which got wrinkled and created ponds of water in the cavity. Typical construction type molds do require three things to thrive. An organic food source. Any construction dust or wood product will do. Moisture above 55% relative humidity. Finally, temperatures in the range of 40-110 degrees. Forget the air, plants need it, molds don't. Since you mentioned that this problem doesn't seem to exist in winter, I'm inclined to wonder if you don't have something trapped in the wall cavity space. I also assume that all of the rope weeps are at the bottom of the wall and none in the higher levels. Are winter temperatures below the optimum for mold?. Have you tried pulling out the rope weeps and looking into the wall cavity? Are there windows in these walls that may not be sealed properly and could be admitting water to the wall cavity?

Hi Home Care Club & Maintenance 6,
Thank you for your feedback. Here is some additional information as requested:

I think I'm safe ruling out interior finishings because we have experience the smell the first summer in the home (we move in winter 2003), and we moved in the house with bare subfloors, only primer on the walls, and no window coverings. Carpet, finish paint, window blinds, and furnature have been added as we lived in the house, and the smell has always been there every summer.

The house is a ranch located in notrhern Illinois, USA - Winters consistently below freezing, Summers in the 70-80's. The 2 rooms with the smell are next to each other on the 1st floor (basement unfinished), with both rooms facing south (windows also face south). 2 of the 4 walls in each room have the brick veener, and the south facing walls in each room have gabel ends which have the brick veneer running the entire height (top of foundation to gabel peek).

Flashing mtl is not metal, but a thick gauge black ploymer mtl. I can see this sits on top of foundation (at floor sill plate level), and from what I recall, it did turn up against the house wall. The weep ropes (consitently space through out) are on top of this flashing, and come through the bottom mortar coarse. All of this is at least 10" above grade.

I do recall a 1" - 2" gap between the brick and the wall lumber, but I don't know how clean the bricker kept the cavity.

House is forced air natural gas heat and A/C. Duct work thru out for supply and return. Supply is in the floor in front of the windows, and returns are in the interior walls of the rooms.

I double checked the exterior of the window, and they appear to be nicely caulked all the way around the windows.

Any other advice you might be able to offer would be greatly appreciated!!!

Thnaks,
fischler@comcast.net

I'd pull some of the rope from the weeps and look inside to see if the weeps are open completely into the cavity. Rope weeps will do OK to wick accumulated moisture out of a wall cavity, but don't work very well in letting any air circulate. The top of the cavity should be vented somehow to let air move to dry out any condensation. Here are some links that show venting and weep options. I tend to beleive that you have someting going on within that cavity, rather than something to do with furnishings or finishes.

http://keenebuilding.com/UserF...all%20WV%20Flyer.pdf

http://masonryinnovations.com/why_ventilation.shtml

I doubt that the smell is coming from the outside brick veneer or leaks from this. If the bottom of the flashing is the issue, then you should see moisture stains or leaks along the floor level at the box plate area by the sills. This is caused by overflows, But again I do not think this is the cause.

Do you know what type of insulation you have in the walls?

Did anyone check the sills along the basement in this area for moisture? I assume that there is insulation packed in the cavities along this area as well. Did you remove any of this to see if there is any mold or moisture hidden behind this material?

What about taking moisture tests on the walls themselves? You need moisture to produce a smell caused by any mold/mildew. If there is enough moisture present it should show up on the moisture meter. Typically the readings will go up the closer to the bottom of the wall as gravity will pull this dampness down in that direction.
Reason for the questions its very difficult to address smells without being in the home and seeing the construction. Also I had a client who had a bad smell in their home, (me) and after several weeks of checking it turnd out to be a plastic runner that was at the front door that heated up from sun coming in. When it got warm it stunk up the whole house. Once removed it went away. Out-gassing of chemicals is a big issue with new homes. Were called on this many times a year.