Shingles or Clapboards?

[BlackCatIslander]

Our daughter has a cape style home facing north. This north side is the only side that has clapboards and the paint has blistered badly. Because of some rot they are going to replace this side. The other sides of the house are painted shingles. My experience is not good with clapboards and I recommended that they replace the clapboards with shingles. Is this good advice?

[SIKSUKR]

The problem sounds like the exposure and not the material. Northern exposure gets no sun and is vulnerable to mold growth and moisture issues, proven out by the blistering paint and rot you speak of. Might be better served with a vinyl product.

[Kings Bluff]

We have had the same rolled shingles on our house in Alton Bay for 60 years with no problems. This stuff lasts forever!

[DickR]

Blistering paint, particularly when the siding is repainted and unacceptably too soon afterward the paint starts blistering and peeling again (and this on a side that doesn't get baking sun on it), often means a water problem, which ought to be addressed as part of a long-term solution. There are two mechanisms that could result in paint failure of this type.

It is too common for a house to have a great many leaks of air into and out of the house. In the colder months, leakage of more humid inside air into the wall cavity can result of condensation on the coldest surface, the exterior sheathing. The sheathing will absorb water, its permeability will go up, and moisture will pass through to the siding. The north exterior wall will be the coldest, and thus most susceptible to condensation, although this can happen on any wall. Besides Condensation of moisture from air leakage into the wall is one way of getting the back side of siding to get wet.

The other mechanism for wetting the back of siding is rain. Wind pressure can and will drive rain up under the laps and onto the back side of just about any kind of siding. If the siding is held tight against whatever is behind it, drying is inhibited. The sunny sides get warmed during the day, promoting drying. Most of the drying has to come by diffusion of the water through the siding, in the case of wood material, and the paint, and this is what leads to paint failure.

Good practice for applying new siding involves several things. First, there must be a "water resistive barrier" (WRB) under the siding, as a secondary drainage plane, to help deal with water that gets driven behind the siding. The WRB can be a house wrap, like Tyvek or Typar, or simple asphalt paper.

Next, particularly for walls that are exposed more often to wind-driven rain, it's a good idea to provide for free drainage of water from behind the siding. This can be done by using one of the newer WRBs that are sort of wrinkled by design, providing for small drainage passages. A more effective way is either to use a mesh type of material, such as "Homeslicker" (a Benjamin Obdyke product), or to fur the siding out by a quarter inch or more, with screened vent strips at top and bottom. Having a gap of a quarter inch or more pretty much eliminates retention of bulk water by capillary effect. Venting at top and bottom promotes drying between rain events. In some parts of the Pacific Northwest, this "rainscreen" design now is required by code.

Finally, when new siding is cut and applied, the back side and cut ends should at a minimum be primed and not left bare. New siding typically is available preprimed on all sides, but the cuts must be primed.

As much as some people don't like the looks of vinyl siding, being plastic it won't rot, and being hollow behind the surface it provides rainscreen type drainage by design. It still needs a properly applied WRB behind it, though.

[VitaBene]

Consider cement based clapboard as well. Hardieplank is the brand my parents used. It wears like... concrete!

[LIforrelaxin]

There are many idea's being presented here all of which are good. At this point I only have on input to make. If you should chose to go with a wood product, clapboards or shingles. I suggest treating them before hand before putting them up. Shingles can be dipped, and clapboards painted before installing them. By covering all sides with a couple of coats of stain or paint before hand you completely encapsulate the material. This makes a tremendous difference.

My father built a house and used wooden shakes for siding. He had all the shake double dipped in paint before installation. The result was a 30+ year old house with the original siding still in unbelievable shape, and it had only been repainted every 10 years or so....As the house stayed in the family, I helped my uncle paint the place when it was 30 years old.... we found no shakes that needed replacing.

In contrast I have a neighbor who has a property for about 20 years and has twice had issue with his clapboards, and had to go through and replace rotten boards because they chose to install and paint afterwards.

Another note I will make is the difference between painting and spraying stain or paint, I don't recommend spraying either for exterior finishes. In spraying applications the paint or stain is already drying when it hits the wood, and doesn't properly soak in. The last house my parents owned, had the original stain sprayed on... after about 4 years, my father and I restained the house, as it was starting to fade and look junky. After two and in some places 3 coats of stain, hand brushed, we where able to wait almost 10 years before the next repainting. Knowing the current owners of that house, it was repainted recently not because of issues resulting from paint failure, but because they wanted a new color.

Bottom line is this. Proper prep and application when painting the exterior of a home go a long way in determining the longevity of the applicaiton.

[Belmont Resident]

Shingles are not meant to be painted; they must be stained or oiled. If we are both talking about the same thing then shingles can get moisture in behind them because they have spaces between them which allow for water to be wind driven in behind and therefore should never be painted. Stain is a self priming sealer while paint is a surface protectant that is meant to be put over a primed surface. Another alternative is penetrating oil such as Australian timber oil which works well and looks great but should be done yearly until the wood is sufficiently saturated.
Shingles do require more maintenance then clapboards but both have their own unique look and appeal.

[DickR]

I found a good article on the subject of paint failure due to water and drying issues:

http://www.greenhomebuilding.com/pdf/RainScreen.pdf

The problem that the house in the article had isn't necessarily what is wrong with BCI's daughter's house, but it does give some good info on addressing moisture issues.

In addition to what I mentioned earlier, a third way moisture may be getting in behind the siding is incorrect flashing around windows. It has been estimated that perhaps 90% of all house windows in the country haven't been installed correctly, with respect to flashing. When you compound that with occasional mistakes in installing WRB material, top-down with the laps open upward, the only things that save some walls is protection from wind and wide roof overhangs.

When the wall in question is fixed, with replacement of the present siding, the reasons for paint failure on it likely will be apparent. BCI's daughter ought to make sure whoever does the work knows his stuff. It would be a good idea to research the subject of siding installation in order to be able to question the contractor and throw the bum out if he can't satisfy her. There is an awful lot of good information available on the net on the subject of building science.

[Belmont Resident]

You would believe how many homes in this area were built without vapor barrier.
The Dockem shore area at the Governors Island end and Southdown are famous for poor construction just to mention a couple of areas where I’ve had to do minor repairs before painting the house. Pretty much anything built in the 80’s was just thrown up by anyone who could swing a hammer. It’s actually sad when you think of what people are paying and what they are actually getting. Spec houses tend to be of a higher quality.
To get back, a lot of homeowners don't know that you are not suppose to use paint on shingles reguardless of how they are installed. You won't find that info at HD or Lowes though, you have to talk to someone a paint store.