Decision time on Vinyl w Insulation vs Repaint or Hardbyboard

Maybe Constantin has some thoughts

Well amidst other various heating projects, it's contract time with our vinyl guy. 1920s colonial, westchester county, new york. We didn't want to paint due to lead dust from sanding--even with the vaccuum bags--and the continued high repainting cost over the years.

Vinyl--much as it goes against my purer, restoration instincts--offers the chance to add a 3/4" layer of polystyrene insulation board over the clapboards and under the vinyl for air sealing. (in addition to the blown in cellulose).

Hardyboard is way too expensive.

My only concern is the possible trapping of moisture by the vinyl--but as I understand it vinyl is installed loosely. I don't suppose the insulation will trap moisture. I would try to seal any holes/cracks in the clapboard with caulking before the job. Also vinyl hides what might be going on with the wood underneath.

This was an agonizing decision after months and months of considering other options. We even paid for a consult with a restoration company with one of the new low heat infra-red paint strippers, but the cost was sky high.

Any opinions on this?

Thanks,

David

We went with hardyboard for residing our dormers a few years back... it's great stuff, and I couldn't be happier with it. But our house is mostly brick, just two big dormers on the upstairs, front and back. If it had been the whole house, I might have had to beat down my purer instincts...

I think you can do vinyl and make it look good... just be very careful about the product and sizes you choose. Stay away from fake wood grain, and try to match the size and profile of your original wood. Or, drive around town and measure the clapboard size(s) of houses of comparable age that still have their original siding.

-Garret

My aversion to fake grain is mostly aesthetic, though I imagine a smooth will be easier to clean (powerwash) in the future. Original clapboards were sanded smooth... rough sawn cedar shakes are another thing, of course. It just bugs me when stuff pretends to be other stuff.

We got pre-primed hardyboard, and painted it before installing. There were a few nicks and scratches... nothing that required major repainting once installed. It's only been up a couple of years, but so far I'm happy with it. We'll see how long it holds up before needing more paint... I'm hoping we'll get 10-15 years out of it.

4.5" sounds pretty good... when we did ours, I ran all around town and took measurements, and found that original clapboards were either very small (2" - usually on turn of the century victorians) or in the 4-6" range (a bit later).

Good luck... sounds like a big project and a big decision... never easy.

I think a major key to looks is how the trim is treated. Cheap contractors are butchers. I good contractor will maintain the size of the trim by sheathing it in aluminum.

While I would prefer natural siding, I now laugh all the way to the bank as my neighbors shell out $7000 every five years to paint their houses that start peeling in a year or two.

Well that was the answer I was afraid of

that the 3/4" polystyrene insulation layer over the clapboards will trap moisture if installed tightly. I have read material from buildingscience.com and it is a bit hard to follow. (See attached pdf 'vapor barriers and wall design' if the Wall allows pdf attachments.) If you look from page 9-13 or so (starting from the RIGHT side of page 9) they seem to say that less than 1 inch of unfaced polystyrene is greater than one perm, i.e. semi-permeable. A number of dewpoint tests are performed at various relative humidities and temperatures.

Joe Lstiburek says, "...No assembly constructed in climate zone 4, 5 6 7 requires a Class I vapor retarder (i.e. a polyethylene vapor barrier)." (This is also from 'Builder's Guide to Cold Climates.') I know this goes against alot of long-standing building practices.

Perhaps installing the polystyrene loosely is the answer OR installing an HRV or ERV in my home to vent out humidity via controlled ventilation.

I have seen studies of some of the PERSIST systems, which use very thick external insulation that seems to work.

In a post last year, Constantin said, "...The exterior insulation simply has to be thick enough to ensure that whatever dewpoint can appear will only appear in the insulation.." (really talking about the PERSIST system.)
..."A properly sealed insulated exterior wall (EIFS is a favorite exterior covering.) [DG: what's EIFS?] will experience little to no migration of moisture as there is no mechanism for the air to transport the moisture to the sheathing. What little condensation could potentially happen is then allowed to re-evaporate into the house by not putting a vapor barrier on the inside. Some form of controlled air exchange will then preserve IAQ, control humidity levels, etc..."

I know this has been kicked around on the wall a bit; seems some of these issues always come to a head just as I'm close to going to contract.

Thanks,

David

Paradox here: usual concern is moisture moving out of house

and condensing on its way on the wrong surface. (In winter anyhow.) But what's strange is that in the northeast house air gets very DRY, usually around 25% RH without a humidifier. So you'd think how much moisture could there be to worry about. (I have seen some condensation on the inside of our bedroom windows some mornings which quickly dissipates when the heat comes on and we open the door.) We have a four degree night setback.

I know that in summer the moisture supposedly reverses direction and comes IN, which is why vapor barriers can be problematic.

As far as a thick enough insulation to prevent condensation where it can be injurious, I do not really have an option to make it much more than 3/4" due to it extending the surface out too far--aesthetic consideration. Another mystery here is that while you and Constantin apparently agree about some
wall systems solving the problem by having very thick external insulation, Lstiburek's charts say that the polystyrene rigid insulation loses its permeability after 1" of thickness.

Complicated stuff.

Thanks,

David

blower test last fall yielded .9 ACH

which isn't that leaky; and that was before we sealed the fireplace flue and blew in cellulose in early spring. we'll have to see how it is next winter. I always assumed the heat was drying out the air. (Back in the city it was REALLY dry with steam heat; always used a vaporizer at night.)

As for the polystyrene insulation, I guess I could pre-drill small holes in it before installation. Of course that gives insects access as well. Or somehow figure out if the 3/4" is permeable enough as it is.

Thanks,

David

Sorry for the late reply,

I have been out with work all of last week and I didn't notice this post before.

This is a hard decision, particularly as you are constrained to only 3/4" of insulation outside the clapboards. I have the feeling that the dewpoint may thus occur inside the home, requiring some permeability for the water to escpe.

I have found the folk at BuildingScience to be really friendly. I spoke to them re: my Radon collection system, so if I were in your shoes, I'd draw up the proposed wall construction, make notes about the local climate and then submit it to them to look over. Maybe they can make some good suggestions for free or a small fee.

I'd like to think that if you resort to dense-pack cellulose and seal the interior walls that the water permeation will be cut down significantly. A vapor barrier would be an obvious candidate but you may not be in the mood to tear down interior walls. Interestingly, they do offer VB paint for interior applications, though I have no idea how effective it actually is.

I'd like to think that if the interior is sealed and water no longer permeates outward that you should be fine with the layer of insulation on the outside, as long as the insulation allows the clapboards to dry out. However, I defer to the scientists... and followed their advice in building our wall systems.

That's a good point too...

... we chose the wood siding route because our GC was able to find a great deal of 17'-long clapboarding. The old stuff was too far gone to save, unfortunately.

I am surprised that the infra-red approach to remove the paint is very costly. The device is only $300 and with the helper screwed to the underside of your roof overhang, the progress is pretty quick because you push the heater to the next section while you work. Not an easy job, perhaps that's why your painter is not willing to do it for a easonable price.

Perhaps it's time to find a paint contractor who would be happy to remove the lead paint at a more reasonable price. I'm not a fan of vinyl either, I find the stuff doesn't look any good after just a few years and painting AFAIK is not an option.

yeah we've been going back and forth on this awhile.

I have alot of the same sentiments. In case you weren't aware of the infra red paint remover here are the links.
The infra-red paint remover: http://www.silentpaintremover.com
The site lists contractors who use it.

This old house infrared red episode info: http://www.thisoldhouse.com/toh/print/0,17071,386353,00.html

As Constantin mentioned, the machine is relatively cheap. I thought of doing it myself --have to use scaffolding to do it right-- even one side a year. It would work best on a house that has multiple layers that's never been sanded. I called over Paul Marlowe of Marlowe Restorations.com in Northford CT for a consultation and he demonstrated the machine. The right scrapers are key. He was very helpful. My clapboards had been sanded various times, but it still worked pretty well. The two painters I spoke to don't like to use the accessory that hangs down; they work in pairs or threes. left, center right. one heats, two scrape.

It is amazing to me that as popular as vinyl is and with all the almost ridiculous variety there is in so many things in this country, they don't have 5" clapboards in lengths over 12 feet anywhere so you have double clapboard seams all over the place. People haven't demanded it and the result is alot of tasteless houses out there.

Thanks,

David

around here vinyl only maybe 25% higher than painting

that is if you hire licensed contractors with workman's comp insurance like I always do. Also this is not a victorian painted lady but a 20s colonial....we have projected the painting cost into the future and it comes out to be really expensive, but of course since we're in our 50s we thought how many more paint jobs could there possibly be?

I figure in a few years they'll come out with something in between vinyl and hardyboard.

thanks for your opinions,

David

Siding

Here is a picture of my new house that I am building. The siding is pre finished smooth hardi plank 5" exposure. I made all of the trim myself from koma boards. The house is designed to look like an old craftsman style home.
I would never install plastic on this home.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

thanks but has almost no info on it

they seem to be plugging for dealers. They don't show any colors; I also don't see it on the approved and test list of the vinyl siding institute. I'll check it out though. There's a dealer in my town.

thanks,

David