Drywalling over plaster not recommended for cracked walls

Matching room's other elements comes with big price tag
By: Bill & Kevin Burnett: Inman News
Q: My husband and I own a 1924 bungalow. When we bought it last year, we had the ceilings drywalled to cover up the terrible cracking.

At the time, we didn't think too much about the walls – just patched here and there. As we have lived in the house, we have become aware of more and more poor patching jobs from previous owners.

Here's the question – why not just drywall the walls over the old plaster, instead of removing the plaster as you described in a previous column? If 3/8-inch drywall is used, it seems as if that wouldn't be that much wall space to lose from a room. The baseboards and door moldings would have to be pulled out and replaced, but that wouldn't be that big of a job, I would think.

A: We've often pondered if there might be a better way to tackle some of the projects we've taken on. An unintended reward of our adventures in home improvement has been the chance to think through a project to see if we might come up with a better mousetrap.

We congratulate you for looking for a better, easier way and encourage you to continue. What you suggest is certainly an option, but we don't think Sheetrock-ing over the plaster is the way to go. Here's why.

It requires a lot of skilled work to remove and replace "base and case," all the wood trim around a room's doors, windows and floors – we think more work than removing the plaster.

The job requires good carpentry skills to make the work look right. Even if you have the skills, it is much more expensive to buy the replacement wood than to buy the Sheetrock and mud.

From a preservationist viewpoint, you'd sacrifice all of the old vertical grained wood for modern material that's generally thinner and just doesn't look right in a historic home. Even if the wood has multiple layers of paint, time invested with a heat gun and paint stripper removing the paint will return the wood to a point where a paint job will look almost as good as new.

If the wood is stained and varnished, replacing it with like material will probably break the bank. Make a phone call to a lumberyard and ask for a per-foot price on vertical-grain 1-by-8-inch Douglas fir. Then do the multiplication. Make sure you're sitting down, as you may faint at what you learn.

Replacing baseboard and door molding is not the only wood you'll replace if you go this route. You're looking at installing new expanded doorjambs – to account for the added width of the walls. You'll have to rehang any doors whose jambs have been displaced. Making the doors fit properly is challenging.

Then there are the windows. You'll have to come up with a creative way to expand the window casings – again to account for the greater wall thickness. Another alternative is to replace them. That would be very expensive. Either way you'll compromise the historical integrity of your home.

There's an added bonus to stripping the plaster – the walls are open and ready for upgraded wiring or plumbing and installation of phone lines and television and computer cable.

Tom Krem, a San Francisco Bay Area electrical contractor, recently e-mailed us with these thoughts:

"I've owned several homes in the East Bay and always look forward to doing repairs on lath-and-plaster walls and ceilings as an opportunity to add badly needed wall outlets and overhead fixtures where there are none, and to add sconce fixtures where wanted.

"When the plaster is gone and the lath remains, it's easy to remove the bottom two courses of lath and drill the studs to pull Romex or MC cable to new boxes either cut into the baseboard or nailed to the studs."

Tom's right. We've replaced many a plaster wall, and although it's dirty work, it goes pretty quickly. Our advice is to demolish the plaster, update the wiring and Sheetrock over the exposed lath.