# Have blueboard, need advice



## cgallery (Apr 12, 2010)

I'd like to patch a couple of holes in a rock-lath (looks 1/2" thick) and plaster wall (maybe 1/4").

I picked-up some 1/2" blueboard.

Do I use Durabond over this or something else? Any good primers on how to go forward? When I google plaster repair everything comes back to drywall-based repairs.

Also, I had read some positive reviews of Vario tapeless mud that said they used it to repair plaster. Thoughts on Vario's products? I imagine it will be a challenge to find it in Milwaukee?


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## Nestor_Kelebay (Jun 17, 2008)

CGallery:

By "rock-lath" I presume you mean Gyproc Lath plaster walls.

There are different ways to repair plaster depending on how bad the damage is and how well you want to do the repair.

If it's a round hole in the wall, and you want a fast dirty, and cheap repair, you can simply drill two holes in the middle of a piece of wood that will fit through the hole. String some steel or copper wire through those holes, and paint the back sides of the wood with white wood glue. Slip the board into the hole and pull on the wires so as to pull the board against the back of the Gyproc lath. Now, slip a smaller board in between the wires and wrap them around each other until they're tight and the board is pressed against the back of the lath. Leave that over night and the board will be glued to the back of the lath pretty solid by morning.

Then, paint everything you want your base coat plaster to stick to with white wood glue and use some diluted white wood glue to mix up some base coat plaster and fill the void in the wall. Leave the base coat plaster about 1/8 inch shy of flush with the wall, and then fill that remaining 1/8 inch with drywall joint compound. Sand the repair down flush with the rest of the wall, prime and paint.

A much better way to do the repair would be to use a jig saw or drywall knife to cut the plaster horizontally to the closest wall studs. Then cut vertically up the sides of the studs to cut out a rectange of plaster. Now, use 3" drywall or decking screws to fasten spruce 2X2's to the sides of the adjacent studs. (Predrill your holes with a 1/8" X-tra long drill bit and countersink the holes to accomodate the trumpet heads of the drywall screws of flat heads of the decking screws.) Attach the 2X2's so that they're a little more than 1/2 inch inset into the wall, and then drywall screw your blueboard patch to the spruce 2X2's. Now apply drywall joint compound over the blueboard so it's more or less flush with the surrounding wall. Then, put fiberglas mesh drywall joint tape over the joint around the repair, spread more joint compound over the tape and blueboard patch, sand smooth prime and paint.

Alternatively, you can fasten your 2X2 nailers so they're flush with the adjacent studs, paint everything you want the base coat plaster to stick to with diluted white wood glue, sprea base coat plaster over the blueboard patch, apply your fiberglass mesh drywall joint tape around the patch, spread joint compound over the repair and sand smooth, prime and paint.

Or at least, that's the quick and dirty way and the much better way of doing a plaster wall repair.


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## cgallery (Apr 12, 2010)

Nestor_Kelebay said:


> A much better way to do the repair would be to use a jig saw or drywall knife to cut the plaster horizontally to the closest wall studs. Then cut vertically up the sides of the studs to cut out a rectange of plaster. Now, use 3" drywall or decking screws to fasten spruce 2X2's to the sides of the adjacent studs. (Predrill your holes with a 1/8" X-tra long drill bit and countersink the holes to accomodate the trumpet heads of the drywall screws of flat heads of the decking screws.) Attach the 2X2's so that they're a little more than 1/2 inch inset into the wall, and then drywall screw your blueboard patch to the spruce 2X2's. Now apply drywall joint compound over the blueboard so it's more or less flush with the surrounding wall. Then, put fiberglas mesh drywall joint tape over the joint around the repair, spread more joint compound over the tape and blueboard patch, sand smooth prime and paint.
> 
> Alternatively, you can fasten your 2X2 nailers so they're flush with the adjacent studs, paint everything you want the base coat plaster to stick to with diluted white wood glue, sprea base coat plaster over the blueboard patch, apply your fiberglass mesh drywall joint tape around the patch, spread joint compound over the repair and sand smooth, prime and paint.
> 
> Or at least, that's the quick and dirty way and the much better way of doing a plaster wall repair.


Yeah, this is a shower valve replacement from the dining room side of the wall. So one hole is pretty large and there is a smaller hole up top (where the shower head is).

Can I use Durabond 90 as a plaster base coat alternative? The area is maybe 24 x 36". I'm going to need about 3/16" to 1/4" of build to get the repair flush with the existing plaster.


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## Nestor_Kelebay (Jun 17, 2008)

Instead of repairing that plaster after replacing the faucet, I'd install an access panel instead if at all feasible. What happens if you suspect a leak after all your plaster has been repaired? What happens if you suspect a leak 5 years from now?

Having an access panel on the back wall will allow you to look for leaks around the faucet that would be perplexing without such access.

E-mail Mifab and find out who sells their products in your area. You might also e-mail tech support at Mifab and explain that the hole is going to be in a dining room, and whether they know of anyone who makes an elegant access panel for such situations.

But, it's your house, your money and your decision.

http://www.mifab.com/Catalog/Access_Doors


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## Nestor_Kelebay (Jun 17, 2008)

I've never heard of Durabond 90 so I can't comment on how well it might work.

If you want something just to fill up space, you could go to a garden center and buy some perlite (which is very light weight) and mix that into you joint compound, (along with some water to make the stuff mixable) and use that for the first coat of your repair. I'd paint your blueboard (and everything else you want your first coat to stick well to) with some diluted white wood glue to make the first coat stick better. You can also add some white wood glue when mixing the first coat. The best way to do that is to dissolve the white wood glue in your mixing water first, and then add the mixing water to your joint compound and mix. Once it's thin enough to mix easily, add your perlite.

Then use a rasp or a sharp paint scraper to scrape off the ridges and high spots before going over it with joint compound.


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## joecaption (Nov 30, 2011)

The proper way would be to just shim out the stud with lattis.


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## Nestor_Kelebay (Jun 17, 2008)

What Joe's saying is that you can use 1/8 to 1/4 inch thick pieces of wood to shim up the nailers on each side of your hole as well as any studs in between.

You can even have the shims cut to precise thicknesses at most hardware stores or home center for a more exact fit.

If that works for you, great. What I've found, though, is that unlike drywall, plaster varies in thickness over the whole wall, and so if you're going to do some shimming, shim the least so that you can fill up the space. It's so much easier to fill up space than to try to get rid of "bump" in a corner.


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## ToolSeeker (Sep 19, 2012)

Dura bond 90 is hot mud it would add a lot of strength but is hard to work with. Plaster of Paris may be a better option for the fill.


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