Rough-sawn siding is difficult to deal with

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This article was published 02/07/2006 (7011 days ago), so information in it may no longer be current.

QUESTION — The rough-sawn, vertical cedar siding on the upper portion of the front of my home needs to be refinished. It is stained with Behr super liquid rawhide exterior cedar gloss wood finish. I’m planning to strip the old finish using Bio-Wash Stripex stain stripper. The bottom half of the wall is reclaimed brick. Is it necessary to protect the brick from the Stripex?

–Bill Mazur, e-mail

ANSWER — Stripping off old wood stain and refinishing siding can be a tricky job, especially when the siding is rough sawn. Exterior paint and varnish removers are a relatively new product and you should always consult with the manufacturer for limitations. I will try and provide some general guidelines, without any practical experience with the stripping compound you have chosen.

Rough-sawn exterior siding is a difficult product to deal with when refinishing, particularly with the glossy finished product that you will be attempting to remove. I will caution you that the final result may not be what you desire. The best advice I can give is to test the paint stripper and future finish on a small area that is not highly visible, prior to the entire job. If this is not possible, removing a small section of siding or one that is deteriorated will accomplish the same task. Make sure that the old “Rawhide” can be removed sufficiently to allow proper coverage and penetration of the new finish you have chosen. This may prevent a potential heartache after the effort of the entire stripping job is done.

The property that causes difficulty with finishing rough-sawn wood siding is the same thing one that provides its desired look. The sawn finish on the exposed side of the wood provides a much larger surface area for the stain or finish to adhere. For this reason, the siding can absorb much more stain and retain that finish for a longer period of time than smooth siding. This also provides a more rustic look, which may be the desire in choosing natural wood in the first place. The drawback is that there is considerably more work in removing all of the old coating when it is partially deteriorated. Not only will the “Stripex” be required, but a fair amount of elbow grease and a stiff wire brush will also be necessary. You may find that the effort to remove this glossy finish is considerably more than just brush on and wash off.

To answer your question directly, you should always protect the lower siding material from any upper finish or product that is dissimilar in nature. This not only applies to the stripper but to future stain or paint finishes. It can be very difficult to remove these products from the porous brick and mortar below. Protection with relatively heavy polyethylene sheathing, taped in place, should accomplish this task. It will also make your clean up considerably more easy.

The other consideration is the caustic qualities of the paint stripper. Most paint and varnish removers are quite corrosive, using sodium hydroxide or other harsh chemicals, to peel of the old finish. These chemicals, in high enough concentrations, could cause discolouration or efflourescence on the brick and mortar below. It is doubtful that this will do any physical damage to the brick veneer, but any chemicals that leak onto the surface should be washed off as soon as possible with water, to dilute them. Special precautions should be taken to protect oneself from harm from these corrosive agents. Rubber gloves and heavy, long sleeved shirts should be worn to protect skin from the chemicals splashing, when washed off. Eye and hair protection may also be necessary to prevent injury. Also, extreme caution will be required when climbing on ladders or scaffolding as the corrosive properties of the paint stripper can cause horizontal surfaces to become very slippery.

The final area of concern is not only protection of the brick veneer, but also other surrounding components of the area to be stripped. Soffits, fascia, and window and door trims should also be protected to prevent unnecessary additional work. Surrounding plants and grass should be heavily dosed with water prior to applying the stripper, to further dilute any chemicals that wash on to them. Sidewalks, driveways, painted flashings, and roofing materials may also discolour slightly if too much paint stripper is accidentally spilled on them.

To sum up the answer in a few short words, use common sense. Anything strong enough to peel paint and varnish, which has withstood years of sun, rain, snow and our extreme temperature ranges, may cause damage to other house components, as well. Always read the directions and warnings on the product containers completely before beginning the process. As with most things, a little extra preventative care may circumvent a small disaster, later.

Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and the President of the Canadian Association of Home & Property Inspectors – Manitoba (www.cahpi.mb.ca). Questions can be e-mailed or sent to: Ask The Inspector, P. O. Box 69021, #110-2025 Corydon Ave., Winnipeg, MB. R3P 2G9. Ari can be reached at (204) 291-5358.

trainedeye@iname.com