Whose responsibility is mold prevention?
Architect requests that I bid for a basement finishing job from his plans. The house is 6 yrs. old, poured foundation, half above ground, completely dry. Architect calls for Sunny Dry powder paint on foundation walls, 1″ rigid foam against foundation walls, 2×4 metal studs on 24″ oc, 1″ + 2″ rigid foam in stud bays, 6 mil vapor barrier, 1/2″ drywall. After my bid is acknowledged, architect calls to say that he and the homeowner like my numbers and want to sit down with me found out if they overdid it on the mold management items (foam, paint, vapor barrier, etc..) and if I have any suggestions where they could eliminate materials and thus cost. He goes on to point out that if mold becomes an issue after they project is complete then he and I are liable. What insight do any of you have here?? As far as I am concerned, I council and put in my 2 cents on many client decisions but I am not a mold/moisture prevention specialist and do not expect to do anything more than install what has been assessed by a professional in that area as the proper materials to prevent mold/moisture. What do all of you think? Thanks in advance for all replies. Bill
Replies
If you believe that the archy has designed something that will promote mold growth, then you are obligated to advise him. If you think there is a better way, you should advise him. But as long as you cover your butt and build to his plans and specs, he's on the hook. That's why archys tell everyone to hire them ... cuz they know building science better than anyone and they will prevent problems that woulld arise from poor design. So let him earn his fee.
Whenever you are asked if you can do a job, tell'em "Certainly, I can!" Then get busy and find out how to do it. T. Roosevelt
An architect does not carry the same credentials as a building engineer. Have him back up his assembly technique with an engineers stamp. Then make it clear to everyone you wont be held liable for his design concept.
Around my area local code dictates the use of a vapor barrier in a finished basement. I dont agree with that especially when there is no airspace between perimeter walls and the foundation. Concrete wicks moisture into the building. Where is the moisture supposed to go?
This may spark some argument but I think no vapor barrier should be used. Moisture in the conditioned space should be controlled by ventillation and with a dehumidifiing system. Ref: FHB 132 Pp.101
Sorry, don't know about mold liability, but it sounds to me like he is specifying the vapor barrier on the wrong side of the wall. VB should be against the concrete if one is to be used.
I think the archy is just trying to pass the buck...
VB should definitely not be used against the concrete.
[And we're off and running in the Rez Bagle Race here]
I know why is sometimes gets recommneded, but if there is moisture coming in through the crete wall that needs stopping and cannot be stopped with the poweder paint, Thoroseal or otherwise, then the plastic will still let it in and it will run to the bottom of the wall assemblyu and ruin the flooring or wick back up in the wall.
Conversly, if moisture from the interior migrates outward through the wall assembly, it will be stopped at the plastic on the inside where it is now trapped.
This basement is reported to be dry now in the humid part of the year, so that is a good sign, and the design sounds good as well, if the execution is strenuously done according to best practices.
But as to the original Q - if an archy started from the beginning pointing the finger at me like that, attempting to get me to agree to share liability with him, I would either laugh, run, or start adding dollars to the bid as well as wwrite several kinds of disclaimers into the contract.
The reason is that a blanket statement about "any" mold is patently rediculous. Mold and its spores are a part of our environment as much as oxygen and carbon dioxide are. O2 is better for us than CO2 but who can blame nme if a location has more of the latter and less of the former? Mold is a hot topic in the HO press and in the lawyers back rooms and the insurance adjusters concerns too. It should be adressed by all of us in this industry but moving in a positive direction does not happen when blame casting starts up front. That is no way for people to work together for solutions. So I would set the archy straight on that right off, and right in front of the owners. I would do it as tactfully as possible, using salesmanship to explain why I would want to be as carefull to do the best job possible and to point out that doing the best while avoiding cost or trying to decrease cost while demanding tgreater liability are incongruous.
I would be reading the people and there reactions to measure in my own mind whether I am dealing with someone looking for the best job or whether I am being set up.
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if you control the moisture would you have mold?
No, if you keep it low enough
"It is as hard for the good to suspect evil, as it is for the bad to suspect good."
-- Marcus Tullius Cicero, statesman, orator, writer (106-43 BCE)
Mold needs food, moisture, warmth, and O2 to grow. Deny it any of these, and it will simply hibernate.
Dust in the air, some glues in products or caardboard boxes and parts of the house can all bne food for it. We need warmth too, as well as th eO2, so reducing the moisture content is the easiest way to prevent it from growing and spreading. Moisture from condensation in the air can be a prime source for the mold. Reducing that by conditionintg the air helps as well as keeping it from getting to a coler condensingsurface.
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gee, garsh.. piffen... this must be the 2d time i've disagreed with you..
the VP should be against the concrete..
moisture will move by vapor pressure from wet to dry..
the earth is infinitely wet compared to the interior of the dry basement.. when the vapor comes thru the concrete wall ( as it will .. since it's a basement , not a boat )
during some parts of the year, this will be a condensing surface.. the water will collect and run down the VB ... if the VB was installed BEFORE the slab is poured it will follow the VB down to the crushed rock we always install under our basements ( we overdig our holes by 12" and install 12" of 3/4 stone)..
the stone also has a VB over it to keep moisture from comming up thru the slab..
anyways , in our basements we use a damproofer on the exterior and a VB on the interior.. and we insulate the slab and the walls
next item... if there is ANY way to get a drain to daylight from below the basement floor.. or to hook into a gravity drain.. we install a floor drain.. surprising how many busted water heaters have been of no consequence because of floor drainsMike Smith Rhode Island : Design / Build / Repair / Restore
"this must be the 2d time i've disagreed with you.."
That count wouyld be disallowing any comments made in the Tavern of course, you flaming liberal
LOL
But if I understand you here, you are talking about doing the whole system in a new basement when you are building it. This case is a finish in a basement that somebody else built. Put platic on the wall in this one and it will not guide the water to the underslab drainage system. I will just dump liquid water on the slab floor where the bottom plate and studs will wick it up into the wall assembly again. Better to let that moisture stay in vapour form and move through the wall into the room with no plastic at all on either side, don't you think?
Every job is different, but i have been thinking more on this subject. - the legal liability one. if i had to do a job lkike this and take on some liability, I would not only add to the price for the risk, but I would throw out tyhe archies plans, not because they aren't necessaarily good, but because they aren't mine, while the risk is. If hew wants it to be his plans and specs, it better be his risk.
Then I would make absolutely sure that I was confident that the exterior waterproofing and drainage systems were satisfactory and write into the warantee that any change in drainage systems on the exterior or failure thereof would void any assummed, implied, or expressed warrantee...
Then I would have A polyurethene foam containing Borates sprayed on the interior of the concrete walls about three inces thick. I would probaly do the framing first so it could be standing about an inch or two away from the crete and would be encapsulaed in the foam.
The foam would be an additional seal against either form of moisture ands against condensation.
I would add some form of conditioning the air as needed - dehumidifier, standalone, ducted in, or excahnger, or wahtever was appropriate, and I would include the necessity for the owners to run it, maintain it, and keep it clean and state that failure to maintain a relative humidity of no more than 40% (with a recommended of 20%) would void any...
What would you do?
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in this one i would drop the 6 mil poly from the sill to the floor and pull it tight into the room with an overlap.. my shoe would be PT..
any moisture would collect on the floor behind the shoe or under the shoe.. and , yes, you bet i'd have the owner buy and install a dehumidifier before we left the job..
if the poly is tight enough, the vapor is not going to penetrate, so there will be a zone of moisture right at the interface of the concrete and VB.. this will help to reduce the vapor pressure ( wet to wet.. instead of wet to dry )
but that's just what this flaming liberal would do... hah, hah, hah
edit:.. some situations beg for trouble.. like standing water under a crawl space with a seasonal water table of say 6".. in cases like those.. we've gone under and sprayed everything, sills , band, and subfloor, with Bora-Care.. pretty good stuff..
documenting things like this is a good idea, as you pointed out... IE: non-standard conditions that have no great solution but can be managed as long as the Owner will take responsibility
Mike Smith Rhode Island : Design / Build / Repair / Restore
Edited 7/17/2004 10:38 pm ET by Mike Smith
Hi Mike. I've got to disagree with your VB, based on what I've read at buildingscience.com. It's a complex issue, though, and you may be one of the guys who can make a VB work.
AndyArguing with a Breaktimer is like mud-wrestling a pig -- Sooner or later you find out the pig loves it.
if you could stop the moisture from the outside would you have a mold problem
Doesn't matter where the moisture comes from:
Oxygen, proper temps, proper PH, food, and moisture = mold growth.
Pretty unusual to see mold growth on raw concrete, in my experience; I suspect it's the PH.
"It is as hard for the good to suspect evil, as it is for the bad to suspect good."
-- Marcus Tullius Cicero, statesman, orator, writer (106-43 BCE)
Hi Guys.
For many years I run a CO.specializing in water and fire restoration. The insurance CO's have a system in place to control the reconstruction expences. They call it..Aprooved contractors list.
This is the biggest scam ever against the legit construction industry and the Policy holder. They (pressure) the homeowner to hire one of thir recomended contractors by promesing a speedy and guarantee reconstruction.
And they throw in few backs for some stupid things in order to get their man in to a contract with the homeowner.
I was a (general) sub contractor for few of this so called construction Companies. My job was how to cover up things and make everybody happy.
They try to keep the word mold out of the insurance dictionary. And they dit. But not me. I make sure in every job to informe and educate the homeowner and get the job done right and mold free every time.
It was a love/hade relationship between the homeowner/insurance/contractor/building inspectors/some times architects and me. It was not fun to work under this conditions but I survive for many years do to the need of my specialties.
But I'am sure many other subs was forced to play the game and that millions of families live today on mold infested houses. Because where was fire was water and all the ideal conditions for the mold and the scams to make a living.
Hi Mike, Hi Piffin.
Yourcarpenterfriend
Dino
hi , dino...
gonna be using my ez guide any day now !Mike Smith Rhode Island : Design / Build / Repair / Restore
Hi Mike.
Thanks to you and others like you the Ezsmart is taking off. If you have the time visit our new site to see how many other tools you bought with it.
I don't want to highjack the mold issue because is very interesting and important health issue. And I feel terrible to know that many people are swipping this issue under the carpet.
Good job guys. I thing the mold issue is everybodys responsibility. And I like to see more from the building inspectors the architects as well from us.
Thanks Mike.
Yourcarpenterfriend
Dino
Gonna demo it at the Fest?
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
i was hoping dino would show me how to use it...Mike Smith Rhode Island : Design / Build / Repair / Restore
"if you could stop the moisture from the outside would you have a mold problem"
There isn't any yes and no answer on that, but I'll put in another nickles worth.
That cellar that I worked on last winter to deal with water problems coming though at point where poured wall sits on ledge and runs across the crete floor to the drain.
When they called me to see it, they had a wood floor that someone had put down. It was PT sleepers nailed down to the slab, covered by plastic VB, and then particle board for a flooring material ( we can shoot the guy who thought that one up later) apparantly to get a smooth dry walking surface and let the water drain underneath it.
It had turned into a multi-rainbow mold farm.
We tore out the old, washed it all down with clorox, and laid in a drainage mat, then poured a new slab over the old, with it turned up at the wall and trimmed off at top of slab after the pour. The rest of the winter and spring, I revisited the job several times and it was always dry. There were two places where water could be seen weeping through cracks in the walls and finding it's way back under the mat and flowing fine to the drain so all the other surfaces were dry even up untill mid June.
Then after the owners came up at the beginning of July, I went by to visit with them and help the old guy put stuff back on the shelves down there. I was amazed to find that all the concrete walls were running with condensed water, and every surface I could touch down there was damp to touch. A set of Particle board shelves had blossomed with mold totally in just those two weeks.
They went into the trash trailer.
In the process, we discovered a dehumidifier in the accoutrements put away up in the corner. I immediately plugged it in to see what it would do and if it worked. By end of the day, it was noticeably better down there, even tho we had often openned the hatch to take trash out.
The wife made a comment, "Oh yes, that old thing! Somebody put that in down here for us but we never did use it at all"
So I sat them down and gave them a lesson in mold growth and the health of the house. I strongly advised them to keep the doors and windows of the cellar closed and to leave the dehumidifier turned on, pointing out how much drier it was already.
I stopped in again last weekend to pick up and drop off some things for them. Guess what?
The dehumidifier was unplugged and the walls were wet again, as were all the surfaces, like shovel handles, oars, ladders, etc. I replugged it and when I was back there the following day, the walls were almost all dry again.
Unless there is a saturation of dust to feed the mold spores, I doubt that you would get growth in the crete itself, but the condensation from humiod summer air hitting the cooler cellar surfaces will definitely provide the moisture needed to go with the food, the O2, and the heat, to grow nice blossoms out of tiny spores.
You must have a point you are driving at siunce you repeated forms of this same Q twice._________?
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Even if you could stop all moisture from penetrating the concrete wall..... When the wall is cooler than the air inside you'd still get condensation on the surface of the wall, right? Yes, you could hope to prevent the condensation with insulation, but I'd never bet on it being an absolute end to the condensation.
Like Pif said, are you driving toward a specific point?You're unique! Just like everyone else! Scott Adams
remember I built my house when I was stupid and un-knoweglable.
concrete block house in the deep south humity 100%. I got a cystal type waterproofer on the inside of block , on the outside two coats of elstaic waterproofer with cement stucco on top of that, no foam board. My walls are dry , always been dry. But I have a VB under the drywall. This was before I learned you do not to that in south. Everybody always preach VB under drywall. I got access port on all four walls so I can peek in to look for mold and moisture( Blank electrical box with backs cut out)
I just wondering if I,m going have a mold problem, been two years now, pretty good so far. No basement outside slope away from house, 8 ft front porch on front.
Oh yea one more thing. the block walls are filled solid with concrete.
Edited 7/18/2004 2:40 pm ET by BROWNBAGG
Edited 7/18/2004 2:40 pm ET by BROWNBAGG
don't worry so much but keep checking once or twice a year. You have enough on the block to teally retard moisture movement to start with, and the temperature differential between inside and out down there is what, 10-15°? But in this basement I am describing, the ground temp at five feet below surface is normally about 55° here with an ourtside temp fo eighty for a 25° differential. Both are right on the ocean so humidiuty levels are similar.
So the diff is that this one has a 25 difference with direct contact between humid air and the cool surface - vs - you have 8" of vapour retarder between the humid air outsdie and the cooler SR surface inside and a lesser temp deference between the two.
Basements are also different from above ground homes in that there is more pressure and potential for capillary action driving the water in.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
>> When the wall is cooler than the air inside you'd still get condensation on the
>> surface of the wall, right?
Depends on the dewpoint. The temperature in Boulder right now is 85F, but the dewpoint is only 55F, so my basement walls can be cooler than 85F but I get no condensation until they get down to 55F. That's also what the dehumidifier in Piffin's example was doing, lowering the dewpoint of the air without significantly changing the temperature of either the walls or the air.
In fact, I've never seen any condensation in the basement here except when I first moved in and found that the dryer hose was venting above the dropped ceiling. Don't know how long that had been that way, but even with that overdose of moisture I didn't see any mold.
Which is also the answer to Brownbagg's question, even if the walls and floor were perfectly sealed against exterior moisture, there are lots of human activities, including just breathing, that may introduce enough moisture into the air to lead to condensation and mold.
Thanks, Dunc. Obviously, I have never completely understood "dew point", although I knew it to be a combination of humidity and temperature factors.You're unique! Just like everyone else! Scott Adams
Here is a link to an online pyshcometric calculator.
http://www.engineeringtoolbox.com/8_240qframed.html
You an enter air temp (dry bulb, DB) and RH and it will find dewpoint and the amount of water in the air (gr/lb).
Now if you take that air and don't add or remove any water, but heat it or cool it (but now below the dewpoint) then you can enter the same amount of water (gr/lb) and new temp in the left and find out what the new RH is.
iv'e got BS Cold Climate and BS Mixed Climate.. i think they hedged their bets in both to make a generic text... ie: it's a good primer, but we can do betterMike Smith Rhode Island : Design / Build / Repair / Restore
Mike
If you have the Taunton versions I think that the version that they point to an oline source is updated and have mover versions that the Taunton ones.
I know that the climate charts (house that work) have changed.
They have a downloadable file specifically on basements.
Mike, there's a lot more on the website than in the books.Arguing with a Breaktimer is like mud-wrestling a pig -- Sooner or later you find out the pig loves it.
I am not a building pro at all.
But from my limited experience what I think is the best system is 2" of xps foam against the foundation sealed so that air can not get behind it.
It is a vapor retarder and it will keep the inside surface warm enough that you won't get condensation.
Then you supporting wall for the DW and the DW. If a little moisture does get in from the outside it can dry to the inside.
Check out the basement insulation article in the research and paper section of http://www.buildingscience.com
If no mold is the goal, don't try to finish a basement.
"It is as hard for the good to suspect evil, as it is for the bad to suspect good."
-- Marcus Tullius Cicero, statesman, orator, writer (106-43 BCE)
First I would laugh at the architect like Piffin says, then call your attorney and get a clause in the contract that releases you from liability and holds the owner's consultants liable for their work. You didn't build the basement... you didn't pour or waterproof the walls, and you didn't pour the floor with rock and a VB under it. Regardless of what the archy designs or what you install, you have virtually no ability to influence mold issues and you should take no responsibility for doing so. REPEAT: you did not build the basement. What the original builders did or did not do is 99% of the issue re mold there.
There's a good clause in the JLC legal kit relating to the owner's consultants and their responsibility for the performance of their designs. Buy the book and charge it to the job!
Wow! You have an archy and his client that are all whipped up about "mold management," and they put a big set of plans and specs in place to "manage" the mold, but now they want to take out some of the preventative measures to save money, but still want the mold "managed" at a zero tolerance level. Right?
There is no way I would ever get on the hook for that one. Follow Pifin's advice.
"Mold" seems to be the new "radon."
This, from the BuilderOnline site:
"Mold Tops Builder Concerns"
"A tally of builder and homeowner inquiries shows that both groups have become keenly interested in learning about mold. Each month, the NAHB Research Center in Washington fields and records housing-related calls from builders, homeowners, and others from all over the country. The NAHB's numbers, although anecdotal, demonstrate that builders have good reason to be scared."
Edited 7/18/2004 1:53 pm ET by Bob Dylan
I'd check with your insurance company if they are excluding mold coverage..many are and it's impossible to get mold coverage. As some have said, you did not build the basement. If there is a pipe leak or sump pump brakes and the homeowner is away on vacation..no VB or concrete wall will stop the mold. It's not your problem as you did not build the basement so exclude it or have the architect design a system that's mold proof which is impossible and have him take all responsibility.