How to install cedar siding

Q. My question for you is about the correct way to redo the siding on our house. Our house is a Garrison colonial style built in 1985. I like the look of the traditional wood siding with canyon gray semitransparent stain. Over the 33 years the spruce clapboard siding has cracked and cupped extensively, especially on the south side of the house shown in the photo. I think the siding needs to be replaced. The siding is nailed directly to oriented strand board sheathing. There is no Tyvek house wrap or tar paper but the joints in the sheathing have been heavily caulked, so the house has been fairly tight with little air infiltration. The sheathing seems to be in good condition.

I am leaning toward replacing the siding with class B cedar clapboards, though I have not ruled out using hardie board. My questions deal with your thoughts on hardie board and with how to best apply the cedar siding. A friend of our house had cedar siding applied directly over Tyvek house wrap. The oil in the cedar effectively blocked the Tyvek water vapor permeability and most of his sheathing rotted from water vapor coming from inside his house. When he replaced his sheathing he used tar paper instead of Tyvek and went with hardie board instead of cedar siding.

I am still leaning toward cedar because of the look of our house. The lumberyard has recommended that cedar siding should be applied with a rain-screen constructed with furring strips to provide a vent space to dry the back of the siding. There are commercial plastic wraps that provide a breather space: for example, "home slicker rain screen" (benjaminobdyke.com), WaterWay (www.stuccoflex.com), DriWall (www.keenebuilding.com). Do I need a house wrap? If so, what would be the best wrap to use? And do I need a rain screen to provide a vent space behind the siding?

A. You are fortunate that the OSB sheathing is still in good shape in spite of the clapboard installation. I have seen a number of cases where this type of installation resulted in rotting OSB because it can't get wet often before beginning to disintegrate.

I am with you; cedar clapboards are best for your style house and this is how to install them properly for a long lasting job:

• Prime all sides of the cedar boards before installing them.

• Install house wrap over the sheathing as protection against any weather infiltration.

• Provide a rain screen either with vertical furring strips 16 inches on center or use one of the commercially available rain-screen materials available in building-supply houses. Benjamin Obdyke Home Slicker Plus Typar offers a product that, in one operation, provides house wrap and rain screen.

• Follow instructions on the nailing of clapboards to avoid "waving" of the clapboards caused by nailing too hard in some places, crushing the Home Slicker.

Q. A few years ago you wrote about the freeze/thaw lifting effect of winter on fence posts. I saved the article but subsequently cannot locate it. Per chance do you still have that information? As you can tell from the attached picture, I have fence posts that are no longer level with one another. I seem to recall that sand was involved in the solution, but I don't recall much else.

The rise of the fence posts is a bit more obvious if you zoom in on the picture. This fence line used to be perfectly level. Thank you for your help.

A. Looking at the photo, it does not seem as if the posts have heaved too much; it is almost imperceptible, but I could not zoom the photo as you suggested.

Unless fence posts are installed in gravelly or sandy soil, it is best to wrap the part that will be buried with black plastic stapled to them and compact coarse sand around them to within a few inches of grade. Complete the backfilling with native soil humped slightly to shed water.

The plastic will help prevent "bear hugging" if the backfilling freezes and grabs the posts.

I assume you plan on taking the fence down and starting all over. To re-level the posts, you'll need to remove the soil, which now has filled the voids under the lifted posts. This is a good time to dump a shovel full of crushed stone on the bottom.

Q. Would you consider purchasing a 17-year-old home (built in 2001) that has vinyl siding and has never had Tyvek wrap? A home inspector discovered the home we are looking to purchase does not have anything between the siding and the plywood. What are the concerns of current and future problems because there has not been any protection?

A. The lack of a house wrap or felt covering the sheathing is of particular concern with vinyl siding, which is not waterproof. Wind-driven rain and other potential issues related to the installation of the siding require some water repellent membrane to protect the sheathing below the siding.

If the sheathing had been rigid polyiso with all joints taped, this would be considered the water repellent membrane.

This sounds as if the builder skimped on an important element, which would make me wonder what else did he or she cut corners on or omit altogether.

Q. I have a chimney that comes out at the top of the roof. It was built with concrete blocks and faced with bricks, a few years later the brick was faced with slate, now a couple of slate pieces are coming down the roof with pieces of brick attached to the back of the slate. I can see where there is another loose slate waiting to fall. What to do?

A. It sounds to me as if the application of the stone facing prevented moisture absorbed by the blocks and the bricks from drying to the outside.

The moisture could have come from the gases of whatever the chimney is used for or from a leaky chimney top.

The stones, being much denser than both the blocks and the bricks, acted as a moisture barrier. Deep frost caused the spalling you see.

If the chimney is not used, or used occasionally as a fireplace, I suggest you have the chimney cap checked by an experienced mason and any deficiencies found corrected. But if the chimney cap is in perfect shape, and the flue is open to the air, there may be another option. In this case the installation of a tunnel-type flue cap may help.

But if you already have a flu cap on, there is not much you can do about the moisture trapped in the blocks and bricks if the chimney is used to vent a water heater and heating appliance. I would not recommend having the slates removed, which would be at considerable cost and result in significant damage.

• Henri de Marne, a former remodeling contractor turned columnist and consultant, is the author of "About the House with Henri de Marne" (Upper Access Publishing). He continues to take questions from readers for this column and his website, www.henridemarne.com. Email questions to aboutthehouse@gmavt.net.