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Water blisters, lichen problems

Q. I am having nightmares over the Rhino-Shield covering on my house, installed just over three years ago. Large bubbles are in the material that I can slit and hand peel the material, right down to the bare red cedar clapboards, which were also primed with an oil primer and finished with latex paint before the Rhino-Shield was applied. The material has a lifetime guarantee, so when I called several persons, including the owner of the company, they all came over quickly.

They said that the material was probably put on when the cedar was damp, and thus would strip everything and apply a new primer and finish coat, let dry, then apply new Rhino-Shield, adding that there will be no more work till flashing is installed under the clapboards. I never heard of flashing under clapboards, and I think there should also be a total warranty with the new material.

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In addition, water blisters have formed on all three sides of the attached garage. The garage is unfinished, lacks insulation and is unheated, and one of the two doors is open to allow cats to come and go. So it seems unlikely that moisture in the garage is penetrating the walls and causing Rhino-Shield failure.

In the house, a clothes dryer is vented to the outside, the main bathroom has an exhaust fan, and I run a dehumidifier in the basement from spring to fall.

What do you think? I paid $17,000 for the project, so I am hoping something can be resolved.

COMPLETELY FRUSTRATED COMPLETELY FRUSTRATED

A. Hooboy! The only way you can keep from losing that $17,000 is to have the company fix everything their way, although there is unlikely to be a warranty on the fix-it job.

The problem is classic: The house is rather tight, and water vapor builds up in the house despite your use of a dehumidifier, open windows, and exhaust fans. The water vapor is from breathing, cooking, washing, and bathing, and coming up through the basement slab. It builds up until it penetrates walls, vapor barriers, and goes through the insulation and ends up at the back of the sheathing, which is cool, and condenses into water, which continues through the sheathing and pushes paint (and Rhino-shield) right off the clapboards. Moisture is also at fault in the garage, despite all the things you did.

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A cure for this is to take off the clapboards and install a 3/8-inch blanket of Styrofoam insulation on the sheathing, then put the clapboards back. The insulation keeps the sheathing warm enough to prevent condensation. Another cure is to strip off the Rhino-Shield, the primer, and paint to the bare wood, and apply one coat of a semitransparent stain.

As for that flashing under the clapboards, flashing allows water to drain, and there is no need for it. Clapboards are self-draining. Putting strips of aluminum (flashing) under each seam where the clapboards meet end-to-end, will do nothing to keep moisture in or out.

Cure for lichen on stone

The handyman often suggests heavy scrubbing and wetting of lichen on stones (tombstones, that is) and scraping off the softened lichen with a thin wood spatula. This is what Barbara Wheeler of Franklin said works for her: Simple Green, which is citrus based.

Q. I painted a chain-link fence with a galvanized paint to match the old finish, but it all peeled off . What should I use?

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JULIE, FROM DORCHESTER JULIE, from Dorchester

A. Go to a paint store and ask for Krylon's Wrought Iron Paint or Contractor's paint. No primer needed. I think it comes in colors, and also comes in a regular form for painting with a brush.

Q. How can I get scratches out of Pergo, a wood laminate floor?

TOUGH PROBLEM TOUGH PROBLEM

A. Pergo is plastic, and I don't think there is enough wood in Pergo to allow sanding out those scratches. There is no cure.

Q. I filled my wood deck boards with a wood filler — holes and cracks. Now the filler is in heavy color contrast to the wood. Would primer and paint cover it?

JOE HERALD, DELMAR, N.Y. JOE HERALD, Delmar, N.Y.

A. The paint will cover it, but avoid primer and paint. It will peel quickly. If the boards are bare wood, apply one coat of a semitransparent stain. It will last seven years and won't peel. It also might cover the filler. But if it does not, dig it out and tint a new filler to match the stain.


Globe Handyman on Call also appears in the g section on Thursdays. Peter Hotton is available 1-6 p.m. Tuesdays to answer questions. Call 617-929-2930 or e-mail photton@globe.com. He also chats online 2-3 p.m. Thursdays on Boston.com.