Crawling around the attic of our new (previously enjoyed) house the other day, I came across this exactly over the shower, which would lead me to believe that the moisture from the bathroom (no vent – window only) is getting into the attic, but there is no damage to anything under the insulation. Most of the underside of the roof has been blackened (mould) and some furry spots are up there.
In the picture you can see what un-affected wood looks like at the bottom of the 2X4, and at the sheathing next to the vent at the top of the picture.
Since I don’t have cash to replace the roof deck, should I install a bathroom fan and take a wait and see approach, or should I suspect the roof as a botched job? (it was installed 2 years ago) I anticipate a renovation in the next 5 years. I can’t ramp up that schedule though.
Any input is appreciated,
Chris
Replies
Man, sorry about that. I'm not sure the roof was botched based on the picture, though.
You need some sort of vent in the bathroom. I'm in the midst of doing this and I can said its a major PITA - get an electrician to do it if you've got the money. A 3hr job for them.
Also, it looks like you've got some sort of soffit-ridge vent system based on the propavents in the other rafter bays. You need to get one in the affected bay, which appears to be missing one. That will help with the airflow and removing some of the moisture laden air, provided that your ridge-soffit system works otherwise.
As to the rood deck, I can't tell from the pic. Maybe some others have a better idea. I can't imagine you'd have to replace the whole thing though.
Best of luck to you. Attics have a way of ruining days, don't they?
Thanks for the quick Reply Bob,
I was more suspicious of the bathroom than the roof, I think you are right. I already picked up a fan, and will be doing the install shortly. Some folks seem to be in favour of venting through the roof, while others say to go to the eaves. The fan's instructions are unclear but advise that the vent fall away from the fan (downhill) to prevent water from condensing in the venting and dripping back onto the floor. Any advice on that?
The propavements are on every other bay throughout the roof. Installing one is quick and cheap though. Good Idea. Will do that this weekend. We do not have ridge venting, only vents about 3/4 of the way up the roof.
My concern with the roof deck was mostly with the mould spores coming into the house and ruining our health. For mold testing I have been quoted $2500 for 5 samples and a report. I believe they would tell me what I already know (Improve venting, replace affected drywall, replace roof deck, scrub studs with Bleach)
Thanks again,
ChrisView Image
Chris - I didn't notice you're near Simcoe at first. Great area. I go up to Canal Lake almost every year.I plan on venting mine through the eave of my colonial about 12 feet away. I plan on having it go up a bit as soon as is reasonable, and then angle down to the vent, sort of like an inverted V, though the angles can't be as drastic. Big changes in the duct direction will impede airflow. You should use rigid duct if you can as opposed to flexible because it helps with the airflow. You should insulate the duct too, to keep condensation from forming. Make sure you size the fan appropriately (look at efi.org 's fans for example, they have a sizing chart. Panasonic's website is even better.) Caulk around the hole where the fan goes through the bathroom ceiling to prevent moisture and air from escaping.You sure you want to do this yourself? Maybe you're more handy than I am, but its a pain. Use the minimum recommended stranded wire size for your current. Its hard getting all those connections in the fan box. If you are using a fan-lite-nitelite combo use 14/4 wire, provided you are on a 15 amp circuit.Going thru the roof with the vent invites leaks, but may be your only option if the gables are far away or non-existent.Try and make sure the roof vents aren't blocked with insulation when you put in the propavent. Bleach will be a good start to kill the mold.
>>Some folks seem to be in favour of venting through the roof, while others say to go to the eaves. Not through the eaves - run a vent to right under an existing through roof vent.Works fine in my area (NW Ohio)
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Sojourners: Christians for Justice and Peace
With the amount of snow they get where he is, I'd be against going through the roof. I don't know what happens when the vent is covered with a foot of snow and that's also when its most important to get rid of the moisture. Maybe the snow melts enough. Maybe it doesn't and the moisture freezes in the pipe. Maybe he gets snow in his fan. There's no problem with going through the eave if the run isn't too long.
I would have concerns about the moisture/mold surrounding the DWV. Have you checked the flange in the roof to see if it is letting in water? Also, bathroom fans are great and I would have one whenever possible but...... with an open window while showering, you can get rid of a lot of moisture, especially during the winter in cold climates ( have lived that way in a few homes in cold places), just close the bathroom door and you won't lose too much heat. I would worry about stopping heat loss through the ceiling, maybe by a sheetrock box around the light ( in the attic) caulked well and surrounded by insulation, then ascertain where the moisture is entering, it could be from bad flashing around the DWV.
just my 1 1/2 cents....
good luck
Good Ideas, but I am more than a little concerned with th e distance from the shower to the window. I don't think that it is providing enough airflow.
The attached powerpoint shows the second storey of the house and the spots where we are seeing discoloration (I suspect from mold) in the drywall.
Please forgive the drawing if it is less than perfect (I normally do roads, not houses).
Since we are so close to the eaves with the damage, I was thinking I'd run the venting that way, but with the decking in such rough shape, I'm not sure that it would be my best option to try to muck about under it any more than I have to. (It is probably easier to to work with better headspace as well and run upwards to the thru vents.
Your comment about a leaking flange at the DWV is also noted. I will check on that as well.
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Edited 11/3/2005 3:33 pm ET by Dagwood
You're correct about the mold testing. You already know that the problem is there. You've got some suggestions about correcting the problem and preventing a recurrence. Testing can tell you what kind of mold is growing, but the revelvance of that information, even for health effects, is questionable. Spend the money on venting the bathroom, which is a good investment in any case.
Do you have a ceiling light in the bath close to the moldy area? Sometimes they leak moist air to the attic.
If so, check the insul around the elec box. Seems that very moist air is getting into your attic from the bath below. (I also noticed the rusted appearance of the strap hangers in what you termed a "new" house).
The warm moist air is condensing on the underside of the cooler roof deck and causing the mold. Poke at the sheathing carefully w/ a screwdriver to determine the extent of the "rot". If the sheathing appears solid (it will depend on how long this has been going on) you probably do not have to worry about the roof.
You should consider an exhaust fan to remove the moist air from the bath regardless.
Hi Pickings,
Good thinking on the light. We do have one near the spot, but not right under it. I will seal up around it with tuck tape and moisture barrier.
Sorry if I was unclear on the newness of the house - it is new to us, built in the mid eighties.
The roof is springy to walk on, the rot is not right through it. If I can get things to dry out I believe it is still structurally OK.
I will install a roof fan.
Thanks again,
ChrisView Image
"I will install a roof fan."
Might be a typo, but......Please do yourself a favor and vent the bathroom, not the roof.
Also spray the moldy area w/ a bleach solution to kill the mold, and stop it from spreading.
Also, check out the sht rk ceil below the moldy area. Might need at least a good cleaning. Mold LOVES sht rk.
EDIT> Have done quite a few of these myself, and have found it to be less headache to vent out through the soffit. Preferably w/in 6-8 ft of the fan.
Edited 11/3/2005 3:39 pm ET by pickings
Thanks for the correction - I seem to be full of errors today. I did mean ceiling vent. I also mentioned "propavements" - I am sure there are pro's who lay pavement, but what I meant was propavent.
I have checked the sheet rock, and (suspiciously) it is as clean as can be. The Gyproc was laid on 1X4 spacers with the VB between the spacers and rafters. Layup goes as follows (bottom to top):
Fresh Paint
Sheet Rock
1X4
Vapour Barrier
rafters/insulation
When we viewed/bought the house 5 months ago, the bathroom had just been remodelled (new Tub surround/paint/floor). Now I am thinking I can see why. Don't worry, we've already spoken with the lawyer. We are screwed.
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I live in an old house, so I am always pleasantly surprised when there is nothing to fix.
I'm never in a hurry to get lawyers involved. Buy it as is, fix it up.
Do not consider yourself screwed......Enjoy the new tub and paint job, get to fixing the problem at hand, and move on.
Life moves too fast to live it looking backwards.
Good luck
If you have a true vapor barrier, like a polyetheylene sheet, then there might be something else going on, unless the barrier is compromised in some way (likely). Or by vapor barrier do you mean kraft facing on the insulation?Its probably coming through/around the light can. Is all this from 5 months or did you not notice this when you were buying the house?
Edited 11/3/2005 4:21 pm ET by BobS
The VB is the clear plastic sheeting under the blown-in insulation. It is working. When I was up there there was water droplets on the down (bathroom side) of the VB. I suspect that the VB is/was compromised someplace. I will be installing the new fan, vented to the thru-roof vents (easier) using flexible dryer vent. I know its not as good as solid venting, but it is easier and I don't want to be up there any longer than necessary. Then I will spray down the affected areas with a strong bleach solution, and scrubbing what I can get at. Once the fan is in, I will be taping everything closed again with Tuck Tape, and keeping a close eye on the attic.
I fear (really seriously) what is lurking behind the tub surround. It has already started lifting from the wall. I'll save that for another post.
Also will check for leaks around DWV vent and through vents while I'm up there.
Thanks again for your help guys.
ChrisView Image
When you buy a fan, do not buy the $18 piece of crap. Buy a squirrel cage type with at least 90 cfm volume. Install it on its own crank timer and not switched with the light.
It looks like the side of the house with the master bedroom faces approximately north and doesn't get much/any winter sun to dry the sheathing. That much moisture in the attic is not just from the bathroom but from a lot of other ceiling air leakage. I would consider a comprehensive airsealing job for the attic not just for the moisture but to reduce energy costs. The moisture that's showing up in the attic is from warm, moist air and you paid for the warm air!!! See "Keeping the Heat In" at the Natural Resources Canada website.
http://www.nrcan.ca
I'd skip the crank timer & get the digital 5-10-15-20 minutes switch.....
It is working. When I was up there there was water droplets on the down (bathroom side) of the VB
This verifies that your problem (at least in this area) is the bath venting. The droplets on the BOTTOM are from condensation of the moist bathroom air against the impermeable cold plastic. This will also eventually create a mold prob on the top side of the sht rk on the ceil. If it were your vent stack, there would not be any "droplets" on the underside of the VB.
Short showers until the vent is in, or at least open a window, and check the ceil for softness/sag, especially around the light.
Within reason lighten up about the mold spores. I am a physician working for a large clinic that rhymes with a common condiment. We see lots of patients with compromised immune systems and true pulmonary fungus infections are rare. You are in greater danger living in the Ohio, Mississippi River valleys from histoplasmosis, and you don't see people vacating the states of Indiana, Kentucky (although why anybody would want to live there anyway defies logic).
Go to Fantech.com and get one of their fans that you install in the attic. Use rigid vent pipe (be a man and learn to work with sheet metal, not that flexible crap), insulate it so you'll get less condensation. Don't use duct tape. When you get your fan from the nearest retailer they can sell you the real tape. It's metal foil stuff.
>>large clinic that rhymes with a common condiment.The Bustard Clinic?
Catch-up Clinic?
The Felish Clinic?Ahhhh.....
The Miracle Flip Clinic!Questions re histoplasmosisAs a home inspector, when inspecting attics, if I see "mouse droppings" on the floor or insulation, I look closely (getting my eyes within a half a foot or so) to see if there are shiny flecks in them, an indicator they are actually bat droppings (the shiny flecks being insect parts.)I don't see them often, and they aren't very concentrated when I do, and I don't disturb them in place.Am I at any significant risk? (Understanding "significant" to be a fairly subjective term.")At what point (degree of accumulation) should I recommend professional cleanup?What would be the risks to occupants from accumulations in attics? (Assume infants, pregnancy or immune system compromised occupants.)
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Sojourners: Christians for Justice and Peace
You should be more concerned with rabies theoretically when around bat droppings. That's usually a matter for the crazy people who are spelunkers. Environmental/occupational medicine is not in my field. Just a WAG...I never worried about it when tearing apart old houses or barns. Prudent action would warrant a face mask for particulate matter. Immune compromised patients would be dopey to be in the attic, crawl space, etc, and a pregnant woman probably couldn't fit.
thanks,re the sensitive, I was thinking of air movement within a house, not them getting into those spaces....
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Sojourners: Christians for Justice and Peace
Go to Fantech.com and get one of their fans that you install in the attic. Use rigid vent pipe (be a man and learn to work with sheet metal, not that flexible crap), insulate it so you'll get less condensation. Don't use duct tape. When you get your fan from the nearest retailer they can sell you the real tape. It's metal foil stuff.
Lucky for me I put in the Solid stuff and bought the foil tape, otherwise I would be questioning my masculinity.
I think the condiment is tabasco sauce incidentally, either that or Tartar sauce. Now I have to go to cooks talk to figure out the reference - oh damn... those women will have me questioning my masculinity again.
Thanks for your input. View Image
I don't know what your lawyer has told you, but that problem doesn't look like a 'hidden vice' to me. It is staring you right in the face if you go up to the attic and look, so it is probably your responsibility to find it during a pre-purchase inspection. A hidden vice is generally defined as something you cannot see or otherwise detect without doing some demolition of the finish work.
A lot depends on the laws in your jurisdiction, of course. I don't think that one would fly very high up here where I am.
Dinosaur
A day may come when the courage of men fails,when we forsake our friends and break all bonds of fellowship...
But it is not this day.
Honestly the lawyer thing isn't a big deal to me - everyone I mention this to brings it up though.
It just bothers me that the house had this in the first place. I understand the sellers thinking though -pretty up the rough spots cheap and fast. Forget the underlying problems. the previous owner had this as a rental property, so I got it for a cometitive price. I also knew coming in that there were some minor things to be fixed. I wasn't expecting this though.
Today I bought an "Air King" 110CFM squirrel cage fan, some solid ducting, tuck tape VB, and the silver foil duct tape... the stuff that actually works on venting. This weekend I'll go up and have some fun before it gets too cold. Here's hoping this starts to make a change.View Image
I haven't read the whole thread, so I might be missing something, but a couple of comments:If you didn't see it or know about it, why do suppose the home owner would?As a home inspector, over the years I come to understand that most problems in attics and crawls aren't known to the sellers. OR they don't understand what they are seeing.Second: from the pic,although it's a little too close in, the mold on the sheathing is no bog deal, I see that regularly above bathrooms. (yours is more than average, but not unusual.)Hard to tell from the pic whether it's a condensing vapor problem or wicking from the edge of the sheathing. Given the proximity of the vent stack, it could be vapor traveling from the subgrade spaces (or even a leak) and condensing on the sheathing. Crawl? Basement? Wet? Dry? (FWIW, most times I see significant mold on roof sheathing there's a wet crawl involved.)I'm a firm believer in the use of legal process when appropriate - it doesn't look to me like this is one of those situations.BTW, their bath remodeling might well have fixed whatever the problem was.
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Sojourners: Christians for Justice and Peace
It just bothers me that the house had this in the first place. I understand the sellers thinking though -pretty up the rough spots cheap and fast. Forget the underlying problems. the previous owner had this as a rental property, so I got it for a cometitive price. I also knew coming in that there were some minor things to be fixed. I wasn't expecting this though.
Were I to do a bathroom exhaust fan install for a client in a similar situation, the total bill would very likely be somewhere between $250 and $500, all inclusive, unless the HO insisted on the very highest-quality super-silent fan on the market. Even with that, the cost of the fix would be unlikely to go much over $750. That, to me anyway, falls into the category of 'minor things to be fixed.'
I understand your uneasiness about finding mould growing on part of the roof structure...but from your photos and description, it really doesn't sound like a big enough deal to make it worth getting one's knickers into a gordian knot. You're on the right track, anyway, in that you are trying to determine the cause of the problem before going nuts, and it sounds likely that you have--although of course you won't know until a while after that fan has been installed. That's just the way it is with these sorts of things....
If it does turn out later on that the problem is being caused by something more difficult to fix, such as bad/inappropriately placed VB, or faulty roofing/flashing/whatever...then you might have something worth gettin' het up about.
Dinosaur
A day may come when the courage of men fails,when we forsake our friends and break all bonds of fellowship...
But it is not this day.
I wonder if you've got air leakage around that plumbing vent? Is it sealed with expanding foam to the wall plate? It should be. Is the fiberglass darkened anywhere? If so, that's because it's filtering dirt from air leaking through it. Find and seal those air leaks, and it's likely you'll dry the attic.
The bath fan is a great idea. Be sure that you insulate the ducts, or you'll get condensation. If the vent goes straight up, it will rain on you. Trust me, I know this. If you go out through the soffits, pitch the duct to drain that way. Going out through the soffit is not usually the best approach, particularly if there are soffit vents. Active soffit vents will pull the vented moist air right back in.
I doubt you need to lose much sleep over the mold. The amount that you have there isn't out of hand. Kill it with bleach or better still, a borax solution (I believe that Borateam laundry detergent will do the job, and it's not so corrosive as the bleach.) Andy Engel
Senior editor, Fine Woodworking magazine
Never try to teach a pig to sing. It wastes your time and annoys the pig.
Other people can talk about how to expand the destiny of mankind. I just want to talk about how to fix a motorcycle. I think that what I have to say has more lasting value. --Robert M. Pirsig
None of this matters in geological time.
I now have a hole in the bathroom ceiling, and the fan housing sitting in place. With the easy work done, I have a couple technical questions before I move on...
Since the fan housing is plastic can I caulk it directly to the VB?
Is it OK to have the fan timer on the vall that the water supply is on for the tub? (This is a wet wall - if it shorts will the person in the tub risk being electrocuted?)
Is it OK for the venting to simply terminate under the existing thru-roof vent or is there some fancy cap or something I need to get?
Should the exposed edges of the drywall under the fan be sealed or treated somehow?
I cut the ceiling right after my sweety had a shower. I was surprised at the Puddles that were on the Drywall. The VB was actually floating.
I am off to the hardware store to get wire and caulking. Thanks again for all your help.
ChrisView Image
"Is it OK to have the fan timer on the vall that the water supply is on for the tub? (This is a wet wall - if it shorts will the person in the tub risk being electrocuted?)"
I don't know how far apart wires and plumbing have to be inside walls, but common sense says they shouldn't be jumbled so close that consensation or leaks would get into the box, or that future work on plumbing could harm the sheathing on the wires. But within the same wall and in the next studspace would be okay.
Codes do say to keep fan and light switches far enough away so you CAN'T reach the switch while in the tub or shower water - to avoid electrocution. I believe it is 4 feet (which is farther than the distance across many old bathrooms).
You should put the circuit on a GFCI unit. Very very important.I caulked the bathroom-side boarder of my hole with Dynaflex 230. Maybe not the best choice but its something. I'd avoid silicone because its a pain to paint (if it doesn't get totally covered) and is a real pain to work with if repairs are needed. Then I put the fan box in the ceiling and screwed it into the wood framing I built up in the attic around the hole so the caulk filled up any irregularities. I didn't seal the drywall, but I'm not sure if I should have. I wouldn't know how to do that anyway. I put the switch outside the bathroom as is customary around here. I'd keep it away from the tub if I were you.I'm not sure how you'd caulk the VB to the fan, but it sounds like a good idea. You should at least caulk it to the drywall, but the fan housing would be better. THe timer switch idea someone suggested is a good one but they are kind of pricey. Add one later if you like, see how you do with just a switch.Best of luck.
Just a quick thankyou to everyone on here who lent a hand in this discussion.
Got the fan in and running fine, finished off the finer touches (drywall around the switch, and sealing the hole around the fan today.
Now when we shower, not only is there less steam in the room, the mirror is perfectly clear and there is no condensation whatsoever on the window. I may have over done the sizing on the fan (110 CFM)
When I went in the attic today to gather up the last of the tools and close everything up, I noticed a water drop on the bottom of every roofing nail protuding through the roof deck... I guess its time start another repair. Shoulda gone up there in the rain before I guess.View Image
I used to live in Alliston and Collingwood and I agree what one of the guys said about the snow at the bottom of the roof. I know you get a lot of snow where you are. As far as venting into your soffit it would depend on the contsruction where your wall meets the roof. You might not have enough room to push through a vent system though you can squash some venting. The other way is if you vent through the roof try to get as high up the roof as you can go. Also you must insulate the pipe. The moist air might condense back into water and drip back into the bathroom. You want the moist air to condense back into water OUTSIDE.
roger
Check w/ EFI for their fan/light switch- automatically runs the fan for a pre-set length of time after the light is turned off.BIll
Could you please suggest/recommend a high quality soffit vent?
Manufacturer and model.
Thanks
Not sure about the "high quality" part, but I have used one from HD (w/ a 3" vent) for the last few years and have not had any problems.
Can't recall the manf, but it is white plastic (which allows for spraying to match soffit) and is pretty "low profile". It allows air out two sides, each w/ a flap that hangs down to close it off when not in use.
There undoubtedly are better ones out there. I was more worried about choosing the correct fan. Incidentally, I liked the fan from Broan (Lowes $89 +/-) . Lots smaller and quieter than the $24 to $79 models at HD, and not hard to install. Coupled w/ a Lutron electronic timer switch (that allows you to choose 5/10/30/ mins of run time.
Also Turn the fan ON BEFORE starting your shower. That way the moist air goes out and does not have a chance to condense on the interior of the bath. You would be surprised how many people wait until done, and then have to run the fan for an hours to "dry out" the bathroom. If you run it while showering, the room is clear and dry when you are done. (personally, unlike my girls, I take 5 min showers, and run it for a total of 10 mins only).