I am working on a house that has problems retaining paint on the exterior northern exposure. The paint is blistered and is falling off the clapboards in sheets. I understand the need to provide ventilation to the wall, but I can’t seem to find any recommendations as to how much ventilation is good, or how often to put the vents in the wall. There are currently two rows of round 1.5″ vents (painted shut mostly), one row near the bottom of the wall, and another farther up, maybe halfway. If these weren’t painted shut, would you think they are adequate. Or should there be more, more often? Is there a rule of thumb governing this issue?
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
Fine Homebuilding is excited to be the official media partner of the 2024 Building Science Symposium series! This event offers builders, tradesmen, architects, designers and suppliers to discuss topics ranging…
Featured Video
Builder’s Advocate: An Interview With ViewrailHighlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Replies
The problem is probably with the moisture in the house exiting through the walls. Walls with northern exposures have no sunlight to dry them so the water hangs around longer. I have cured similar problems by having customers use their outside vented bathroom and kitchen fans more often. Another route is to directly connect the bathroom fan to the light switch. People just don't realize how much moisture is created just by breathing, let alone cooking or bathing. AND - any air exiting a building must be replaced, but the fresh air vent to the furnace takes care of that.
As for roof vents, good idea!
sometimes board sometimes knot
gordsco
It's also a good argument for backpriming the siding.
I am looking at a similar jhob. They have painted three times in six years. I installed shutters as a trim for them this summer and thery asked about the problem and solutions. This is an extremely old house with plaster walls which had never had any vapor bar added to the inside. Then they had cells blown in which trapped the moisture exiting thru the walls. Now they have trouble. When I added these decorative shutters, I noticed that at least a third of the holes I drilled brought out dark brown sawdust (rot) in stead of clean blonde stuff. I'm sure they have a lot of rot. I explained that before I touched it they would need a large open ended budget.
I am proposing to open the wall and discover the extent of damage, Repair, re-sheathe, rain screen wall, Hardi board siding.
My concern is how to prevent the water from entering the wall in the first place from the inside. It will probably mean removing the damp cells and replacing from the outside with faced fibreglass.
I'm open to discussion and suggestions on the same issue here.
Excellence is its own reward!
Seems perplexing to me. Our 127 year old Vic here has plaster walls, no vapor barriers, blown cellulose and we have no problems with the siding or paint on this account. And there's gobs of other houses around here that are identically outfitted and I've seen no repercussions from this arrangement in any of them, either. As you can imagine, things get pretty cold here in northern Il. during the winter.......brass balls and all that. Are the weather conditions that much different in Maine? Higher relative humidities due to warmer days combined with more snow to feed it?
I've done much work on this place since '88, as well as many of those others and I'm sure that if there was a problem present, I would've seen it. The paint on the north side of this house and most of those others always outlasts any other side by 2 to 1 because the north side doesn't see all that much weather. If there was a moisture problem present, it should show on this side first.
I can't help but wonder if there's an issue with the house you're looking at concerning numerous layers of oil-based paint on the siding that won't allow the moisture to freely escape. ???? Just a thought.
Maybe overlay drywall on the interior wall side so you can get a vapor barrier in place after the repairs are done. ?? Gotta deal with those window jambs, casings, and baseboards then, tho. Bummer.
Maybe these folks are doing a lot of home brewing in there. That'll make heaps of moisture I can assure you.
Knowledge is power, but only if applied in a timely fashion.
In my experience, when there are condensation issues, it shows up first on north sides because of cold.
Now that I think more about it, this house was built on piers and was then closed up under with false parge foundation allowing ground water to add to the trouble. The roof has no overhang (one of those things I hate about this eastern architecture) and it has been overlaid with asphalt shingles - not neatly - so it may be letting some water in to the wall. I've got some pics I'll post later but right now, I've got about twelve files open and afraid of overloading system resources and losing something since graphics are big..
Excellence is its own reward!
Piffin,
Not much time here, so I'll be to the point. After seeing those pics, about all I can do is groan. The house looks fraught with potential problems for moisture infiltration. I'm sure none of this has escaped you, so I guess this is to confirm that I see what you do.
1 - No overhangs and no gutters….In numerous areas you can see where the water running down the roof is allowed too cascade right down the siding and in some of those situation, right down on top of lower windows………not good.
2 - Lots of windows. Are there drip caps on those windows and if so are they still functional or might they be rusted away.
3 - Oh Lord, how I hate aluminum storm windows. Around here, 90% of them that I see have the weep holes plugged up. The owners have the lower screen portion open in the summer, the rain pours in and can't escape so it ends up making its way inside the wall via poor joints where the side jambs meet the sill. Usually, they forget to close them come winter, too. Problems in 2nd story windows get the ones below them, as well.
4 - I wonder if any of those dormers have functional step flashings.
5 - How many layers of siding on this house??? It appears that the casings are buried inside layers of ???? How difficult would it be for moisture to escape thru multiple layers of siding and any coatings that are on them?
I'm beginning to be glad I don't own this place. It looks scenic enough, what with the hanging flower pots and all, but I see a constant battle with water as well.
Knowledge is power, but only if applied in a timely fashion.
Well, now that I had a few more moments to look at the pics........I'll retract that concern about multiple layers of siding. The casings don't look all that buried after all.
But I'm still not glad to see those aluminum combination windows on there.
I'm wondering if there's ice damming problems. ????
You said in your original post on this that they've repainted three times in the last six years. I wonder how long they've owned the place and if they know whether the problem is escalating…….the more paint they put on, the faster it throws it?
Knowledge is power, but only if applied in a timely fashion.
Blown cellulose acts as a vapor barrier.
Thermal protection, vapor barrier and firestop. The stuff is great!
sometimes board sometimes knot
gordsco
I'll differ. The only way it is a VB is to let it get stopped halfway into the wall where it is trapped long enough to cause rot.
anyway here's a shot or two of the house I'm talking about, not that the pics show the trouble very well.
****
the attachment button won't work tonight! Oh well.
Excellence is its own reward!
OK here we go.
Excellence is its own reward!
Looks like you're going to be there a while. The insulation blown into the cell?(I assume this is the stud cavities) should have been dry at installation. If it is now saturated, it must have happened after the fact (probably alot of water running down the walls on a house with no eaves and a slightly horizontal driving rain) As for the dark stuff around the windows, it looks like most of those shutters are mounted under sections with soffit overhanging. If you've got rot there I'd change that open ended contract to a career. You'll be spending more time there than home.
sometimes board sometimes knot
Edited 9/30/2002 1:45:12 AM ET by GORDSCO
All poor work. You can see on one shot that the crown style fascia was replaced with modern flat 1x8 and no overhang to speak of. The eave on that one actually has the shingles cut shy of the metal edge. That Corner board has been replced once for rot. These are all details you really can't see in the photos. .
Excellence is its own reward!
Piffin,
See what you make of this and if it's any help diagnosing the problem with the house.
http://www.regalind.com/vaporbarrier.htm
Perhaps one of the paints that claim to act as a vapor barrier would serve these folks if you conclude that vapor entering the walls is indeed the problem.
I still can't help but wonder if the siding has multiple coats of oil paint on it that's preventing the moisture from escaping. I'm probably all wet.........no pun intended.Knowledge is power, but only if applied in a timely fashion.
I've been gone out of town a couple days so I hope I didn't leave you feelong like you were talking to yourself.
Thanks for all the thoughts and coments - a lot of them covered where I said that I was telling the owners that I needed an open budget/blank check before I would open it up. I expect to remove a lot of sheathing, re-do the trim, re-roof and possibly repair some structural work once I get going, before getting to the sioding again.
This house is nearly 200 years old in the original incarnation, then added to about four times and repaired _____times, often by fishermen who needed winter work. Building science on the island is directly related to boat building skills. Sometimnes that's good, sometimes bad. Boat caulking needs to be redone every year.
I can't be cetain of all the history on the paint, but the predominat used here is Ben Moore oil. The latest coats may be compromised by poor prep work, given what I know of the property managers methods.
It is indeed a fine location. One can view the bay both east and west from this lot. I actually mentioned to the owner that the lot is probably worth more than the house and asked if they mioght want to consider tearing it down but she showed me the inside which is very nicely done. Too much invested now toi turn back....
Excellence is its own reward!
Piffin,
I've been spending more time thinking on this than I care to admit. It's a challenge trying to figure it out from a distance….but what can I say……..I love a challenge.
Here's a few of my thoughts and/or questions that should provoke more frustration from your brain.
If there are many coats of oil-based paint on the house preventing vapor escape, what is the likelihood considering the age of the house that there's also oil-based paint on the interior wall surfaces? Shouldn't this prevent vapor entry to the same extent? …..a seeming paradox, perhaps.
Considering the age of the home, can we assume balloon construction? If so, could the vapor be finding it's way to the walls via the ceiling joist bays?……….if and only if the ceilings have been replaced and therefore may not have an oil-based semi/sort of vapor barrier, but rather are coated with latex paint which would allow the vapor to pass into those joist bays.
Is the deterioration of the siding present only in particular areas that are consistent with the additions to the house constructed in a manner that could allow the aforementioned then to come into play?
Okay, I'll stop. Hope you post back on this one when you get it figured out.
Knowledge is power, but only if applied in a timely fashion.
I have been theorizing about it too, and find that this exchange is good in following my thoughts and refining them.
The interior walls are indeed coated with oil based paint which might well be preventing interior moisture from entering the wall cavities. The roof, attic, and crawl space are the more likely culprits, with roof and flashings at the top of the list.
The house is unused in the winter so ice damming is less likely.
Poor craftsmanship in the exterior package is likey a part of it.
A total exterior is definitely indicated with possible exception of a kitchen wing added within the last ten years.
ALAS! I may never find the final answer to this mystery. I'll bet 50/50 that the preent owners will decide, after digesting my leter, to touch up the paint one more time and put one of those little signs out front with a realtors name on it. .
Excellence is its own reward!
If you're correct, would this then fall under the heading of "pass the buck"? Knowledge is power, but only if applied in a timely fashion.
Thanks for your comments ( and everyone elses). I've been working on this house now for a couple of days, so I have a little more information. The base coat of paint is about 75 years old, so I'm removing carefully with an AIM Paint Shaver and a HEPA vacuum. Where the paint is peeling off seems to be mostly over this old oil/lead paint, and the paint that's leaving is latex. So at this point I am assuming that there is some incompatibility between the paint coats.
However, my original question is still pending. How should this wall be ventilated? I have 1.5" plastic vents to install, but I'm reluctant to simply follow the existing pattern and am looking for some expert advice as to how these vents should be installed to be most effective.
I wish I could tell you, but I have no experience in venting an exterior wall for possible vapor infiltration. That's no help, but I wanted you to know that it's not because anyone is ignoring your question. Seems judging from the responses you're receiving that no one's willing to stick their neck out on this one.
I'd venture a guess tho that everyone's approach is likely to be focused on preventing the vapor from getting there rather than dealing with it after it is. That's always the best approach. Maybe stripping that paint will cure the problem for you. Perhaps it's nothing more than a paint problem and there's no moisture problem at all.
Knowledge is power, but only if applied in a timely fashion.
IMO if the problem is all the north face you have a paint problem. If the problem is spotty then it requires investigation.
Spotty would mean is it only from the top down, only around windows, more at floor levels, only under overhang, etc....
Drilling brown punky wood around windows of a 200 year old house suggests damage but determining if it's new or 175 years old can only be done by opening her up and the answer to one problem may no solve the other.
I hate jobs like this, need a bunch of CYA in the contract and shoots a schedule to hell.
Good luck...