Thread: high indoor humidity problem

Hi guys, looking for some suggestions on what could be causes to the problem.
Developer has an existing 2 story + basement, 6 unit Condo building. New full rehab with dramatic moisture problems in the basement and moisture smell in 1st floor. The new Cherry hardwood floors in the basement are buckling and swelling. He has replaced and resanded twice, problem keeps coming back. The problem appears to originate from the center of the building in both basement units and then spread out towards the exterior walls and lessen as it spreads. I'll list some of the details.
- Checked roof, very nice new rubber roof, well done, no signs of problems
- Checked masonry walls, new tuckpointing all around, no efflor signs anywhere, tight all around
- Checked wall to grade, tight joints, grade slopes away from building
- Checked interior hvac, HUM and venting, all OK
- Exterior RH 35%, interior RH 57%
- Checked drywall walls in BA with meter, measures mostly OK with occasional midrange levels, no spikes anywhere.
- Checked RH in sump & ejector pit closets, reads lower than in overall space.
There are two 6" downspouts at the center of the building rear that come down into two 6" cast sewer drains that run under the building to the front and then to the street. My thoughts are that there is a problem with these runs. I can't come up with anything else that makes sense for the amount of damage and moisture levels. Owner states he was present when cast runs were installed and they looked fine to him. (I know) My initial REC is that he get a camera guy to check the 6" cast runs.
Any thoughts or questions are appreciated. Thanks Markus

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Originally Posted by Markus Keller

Developer has an existing 2 story + basement, 6 unit Condo building. New full rehab with dramatic moisture problems in the basement and moisture smell in 1st floor.

The problem appears to originate from the center of the building in both basement units and then spread out towards the exterior walls and lessen as it spreads.

What has the developer said is in those common walls?

Was there a moisture problem before and he just did not notice it?

Could it be water piping (DWV and/or supply) in those walls?

Could it be moisture migration up from under the slab?

Did the developer take photos of before, during, and after?

If he has sanded the cherry floor twice, he might be at the end of its re-sanding ability, depending on the floor type.

For that cost (re-sanding and refinishing the floor) I would first recommend pulling up the base along the common wall in the basement and removing the first 2 feet of drywall (might as well remove the first 4 feet, to the drywall joint, to make the repair less noticeable - but at least to 2 feet).

That will allow you and everyone to actually see what is going on, take measurements, monitor what is happening as you might not see it right away.

A Thermogapher can image the building for the direct points of moisture. He can set the humidity alarms on the camera to pic up the problem areas. you have an entry point and thats what you need to find to correct the problem.

Best

Ron

Jerry and Ron thanks for the responses. I didn't even think of the thermal imaging. Kind of dumb really, considering how much it gets talked about on the Board.
Developer says:
- all exterior walls and interior common walls were cleaned, pointed, and painted with a masonry paint.
- layer of vapor barrier (3 mil plastic type) was installed between ground and concrete
- the floor consists of concrete, another layer of plastic, 1x sleepers, layer of felt and then 3/4" cherry (Unsure of how Cherry reacts to this set-up, going to look into it)
- there are no major plumbing lines along the common dividing wall, baths and kitchens are more towards the center of each unit. I was thinking it might be detached or not installed vent pipes at first. I would think that problem would manifest in the drywall not so much in the flooring
- The developer take pictures? Please Jerry, we both know better than that.
I mentioned to the Client taking off some drywall but he is reluctant to do so at this point. He doesn't see much point for various reasons. I will continue to work that idea.
Ron, I think your idea will probably go over really well and hopefully work. I am going to post in the work section here for a thermal guy to refer. I don't know of one myself.
Thanks, Markus

Sounds to me like the house is really tight and the ventilation is poor. But since the structure is in Chicago can't even give a good reasonable guess other than what I stated.

- layer of vapor barrier (3 mil plastic type) was installed between ground and concrete
- the floor consists of concrete, another layer of plastic, 1x sleepers, layer of felt and then 3/4" cherry (Unsure of how Cherry reacts to this set-up, going to look into it)

I would be taking a closer look at the items as above, 3 mil plastic? Another layer of plastic? 1x1 sleepers?

With the wood floor buckling it sure sounds like a moisture problem as a result of improper or lacking vapour barrier due to leak or high water table.

Originally Posted by Markus Keller

Developer says:
- all exterior walls and interior common walls were cleaned, pointed, and painted with a masonry paint.

Does not do much to stop moisture migration or water vapor.

- layer of vapor barrier (3 mil plastic type) was installed between ground and concrete

"3 mil"?

That's not a 'moisture barrier', that's a 'cheap painter's drop cloth' from the Big Box store.

Most moisture barriers are required to be 6 mil, and some brands of wood flooring require 10 mil.

- the floor consists of concrete, another layer of plastic, 1x sleepers, layer of felt and then 3/4" cherry (Unsure of how Cherry reacts to this set-up, going to look into it)

I thought no full thickness (3/4") wood was recommended for sub-grade applications. Too much moisture.

You stated that there is a concrete slab, moisture barrier under it is unknown - right?, then a piece of plastic food wrap (that's about all that 3 mil is good for), then 1x sleepers, followed by (I am presuming, you did not say) plywood or OSB, with felt on top of it, and then the finish floor.

If that plastic film does any good, it will collect and trap moisture between it and the wood sleepers and the underlayment subfloor above it (if installed, otherwise it is just the 3/4" cherry). The felt *IS NOT* a moisture barrier, it is a 'vapor retarder'. Sounds like the developer is expecting the felt to serve as a moisture barrier, and it cannot, not made to, not intended to.

- there are no major plumbing lines along the common dividing wall, baths and kitchens are more towards the center of each unit. I was thinking it might be detached or not installed vent pipes at first. I would think that problem would manifest in the drywall not so much in the flooring

Unless there is an opening in the slab around the pipe, or the pipe is cracked at the slab.

- The developer take pictures? Please Jerry, we both know better than that.

Sounded like higher end stuff, I had builders take photos of higher end stuff.

I mentioned to the Client taking off some drywall but he is reluctant to do so at this point. He doesn't see much point for various reasons. I will continue to work that idea.

There are always lots of justifiable reasons not to want to remove drywall, and only one justifiable reason to remove it - so you can see what is going on at the location where the moisture starts. May not tell you what you are wanting to know, but if that is where the moisture starts, that is where I would start.

I'd pull a few boards to see if there is condensation under the plastic

Those 1x1 sleepers will rot out in no time.

Thanks for the comments guys.
Jerry I guess I was being kind and liberal with the term vapor barrier for the plastic. I realize the floor install isn't ideal and may be causing at least part of the problem in terms of how the cherry floors are reacting to the moisture levels. Nonetheless I think the key is to figure out the how & why of the high moisture levels.
Someone else mentioned to me a while back about not putting 3/4" flooring sub-grade. I haven't been able to find anything definitive on that though yet. I'll be searching today for info on that and also recommended basement install guidelines over concrete floors. Typically I see a layer of insulation board between the sleepers or under the plywood subfloor that is nailed to the concrete.
Jerry, I don't know how it is down by you guys but up here laminate/engineered flooring still has a bit of a cheapo stigma. Chicago homes have traditionally been built with 3/4 hardwood floors. Oak throughout and Maple in the kitchens, narrow/wide pine and others depending on era and neighborhood. Today, builders, realtors, buyers all look at 3/4 hardwood still. Cherry has really replaced Oak in the last 5 years or so as the boilerplate in higher end places. Laminate is still sort of relegated to the small side office, guest space or back hallway from what I look at, if there is any present at all.
The client is going to pull up some of the buckled up boards and I will check under that area once he does.
Thanks, Markus

I've done some preliminary research and found some interesting info. Most info recommends no hardwood subgrade, some say it's Ok if installed properly.
I've found a few pdf's that others might find helpful and would like to post here so you guys can download for your files if you want.
Unfortunately I'm too dumb to figure out how to do it. So if someone can explain it to me I will post the pdf's.
Thanks, Markus

Marcus,

This ( Bruce Hardwood Installation Guide ) will take you to the Bruce installation instructions.

This ( http://www.bruce.com/content2/resam/files/18898.pdf ) will take you to the 3/4" solid plank and strip products, which says, on Page 1, under Job-Site Conditions, (also see attached capture of that section)

(underlining is mine)

Job-Site Conditions
• The building should be enclosed with all outside doors and windows in place. All concrete, masonry, framing members, drywall, paint and other “wet” work should be thoroughly dry. The wall coverings should be in place and the painting completed, except for the final coat on the base molding. When possible, delay installation of base molding until flooring installation is complete. Basements and crawl spaces must be dry and well ventilated.
• Exterior grading should be complete with surface drainage, offering a minimum drop of 3″ in 10′ (7.6 cm in 3.05 m), to direct flow of water away from the
structure. All gutters and downspouts should be in place.
• Solid hardwood flooring may be installed on- or above- grade level. Do not install in full bathrooms. Installation of a suitable subfloor is required over concrete.
• Crawl spaces must be a minimum of 18″ (46 cm) from the ground to the underside of the joists. A ground cover of 6–20 mil black polyethylene film is essential as a vapor barrier with joints lapped 6″ (15 cm) and sealed with moisture resistant tape. The crawl space should have perimeter venting equal to a minimum of 1.5% of the crawl space square footage. These vents should be properly located to foster cross ventilation (Figure 1).Where necessary, local regulations prevail.
• Permanent air conditioning and heating systems should be in place and operational. The installation site should have a consistent room temperature of 60–75° F (16–24° C) and humidity of 35–55% for 14 days prior to and during installation and until occupied.

Jerry, thanks for the info. I was busy all weekend and didn't have time to get back here.
Markus

Ok, I managed to figure out how to upload. I guess it doesn't matter if it's a photo or not. One pdf made it the other won't seem to upload though.
I hope others find this guide helpful.
Thanks, Markus

urI would never put hardwood in a basement. Anything below grade is going to have a higher moisture content under the basement slab and just moisture in the soil around the basement.

The developer should certainly conceder offering tile or a laminate floating type floor at best.

AS far as running the cast drains under the buildings I am not sure what that is all about. You think it would be set up to go around the building.

The problem is there and the builder has replaced and or re sanded and the concerns is still there. Hello. Nothing was done to address the concern and again my initial comment would certain hold fast. I would never put hardwood in a basement. Typically way to much moisture under and surround the basement floor.

High moisture in the basement and a moisture smell on the first floor. Jeepers kreepers. You think he would have slapped himself in the forhead by now and said. Nope, not putting hardwood in the basement. I take back even a laminate floating floor. Something else to have moistiure under and mold conditions. Tile at best.

Markus,

It's in there too:

(underlining and red text is mine)

INSTALLATIONS OVER A
CONCRETE SLAB.
Hardwood flooring can be installed successfully over a
slab which is on-grade or above grade. Below-grade
installations are not recommended. The slab must be

constructed properly (dry and flat with a trowel finish).

Then this at the very end: (means ... regardless what we say, ALWAYS what they say )

*ALWAYS FOLLOW MANUFACTURERS’ DIRECTIONS

Which means, in your basement unit ... *no hardwood floor should have been installed*.

Some thoughts: What about cloths washer and dryer, bath fans, test under wood flooring?/

Rolland Pruner

Rolland, those components are present but the units are vacant so they aren't being used. So signs of supply side leaks anywhere.