Blueboard

[Dan_Musicant]

I was watching Ask This Old House today on PBS and one segment had Tom Silva demonstrating repairing a hole in a wall using blueboard and veneer plaster.

One particular wall problem in my old house looks good for this technique. I have a bunch of wallboard, some of it standard and some water resistant variety that was used to fix my bathroom. Would that water resistant variety qualify as blueboard? If not, where do I get blueboard? Home Depot? Orchard Supply?

I have a lot of plaster type surfaces (walls and ceilings) that need repairs, and really need to figure out proper repair techniques. For instance, I have plaster falling down from ceilings from time to time! Any suggestions appreciated.

Dan

[Italian]

Im not sure what your asking.. Plaster and drywall are 2 very different materials and repair of each is an individual process. In short for the sake of argument green board is basically the same as blue board. Since you mention OSH you must be out here on the West Coast and blue board is not really avaliable out here...atleast not for the home owner market. You say :I have a lot of plaster type surfaces (walls and ceilings) that need

Is this infact plaser (cement, lime, sand) or is it drywall compound? You can tell very eaisly by the texture of the material that has fallen off if it is plaser it will be very sandy, if it is drywall compound it will be chalky and soft very much like a piece of chalk from school. If it is plaster you must remove all of the loose material then you can patch it with drywall compound.

Dan_Musicant wrote:

[Dan_Musicant]

:Im not sure what your asking.. :Plaster and drywall are 2 very different materials and repair of each :is an individual process. In short for the sake of argument green board :is basically the same as blue board. Since you mention OSH you must be :out here on the West Coast and blue board is not really avaliable out :here...atleast not for the home owner market. :You say :I have a lot of plaster type surfaces (walls and ceilings) :that need :> repairs, and really need to figure out proper repair techniques. For :> instance, I have plaster falling down from ceilings from time to time :Is this infact plaser (cement, lime, sand) or is it drywall compound? :You can tell very eaisly by the texture of the material that has fallen :off if it is plaser it will be very sandy, if it is drywall compound it :will be chalky and soft very much like a piece of chalk from school. :If it is plaster you must remove all of the loose material then you can :patch it with drywall compound.

You are right in that my post was a hodge podge. IOW, it was about more than one subject, but I thought to say more than I maybe should have said in a thread addressing "blueboard." In fact, there is one small damaged area I have that's in a drywall-like material. I say that because it probably predates modern drywall. I did a repair of it years ago but it wasn't satisfactory and now (after a partial remodel of the close-by bathroom), my plaster patch has come loose entirely and it needs to be fixed properly. It's small (less than a square foot). A drywall patch such as I saw yesterday on Ask This Old House, would work. Tom Silva cut a piece of drywall that was rectangular (and about 4 foot square), traced the outline of it on a wall and cut out the wall along the trace lines. He affixed 2 backing strips with drywall screws and attached the patch to them (with more drywall screws) and covered the seams with fiberglass tape, and the whole with veneer plaster. My description is sketchy, but gives the general idea.

Aside from that one repair problem, I have a lot of plaster problems in the house. Yes, it's mostly plaster of various kinds. There's very little drywall here - almost none. The house was built in 1913 and, of course, modifications (and additions) have occurred since. There seems to be not much drywall compound, but I'm not sure of that. Most of the imperfections I speak of are clearly some kind of plaster problems. You are suggesting I repair them with drywall compound. I really don't know what to do about a lot of it. There's a lot of such problems, and maybe some should be addressed differently. One room in particular has plaster coming loose from the ceiling. Obviously, I can remove some (a LOT!) that isn't now well-adhering to the material above the plaster finish coat, which itself is probably lath & plaster. Somehow, the finishing plaster apparently wasn't properly applied in the first place, but maybe after 90+ years it's no surprise. Removing all the finish plaster might be difficult (if it's adhering in places), and naturally, it would be one messy messy job.

There are other not unusual types of plaster problems. Holes, broken out places, and worse - areas that aren't necessary broken out but are bulging. Obviously, those bulges should be broken out and repaired. I think I should get myself an education on old home renovation! I'm seriously thinking about taking some local classes, and I have a few books and some hardware store handouts.

Dan

:Dan_Musicant wrote: :> I was watching Ask This Old House today on PBS and one segment had Tom :> Silva demonstrating repairing a hole in a wall using blueboard and :> veneer plaster. :>

:> One particular wall problem in my old house looks good for this :> technique. I have a bunch of wallboard, some of it standard and some :> water resistant variety that was used to fix my bathroom. Would that :> water resistant variety qualify as blueboard? If not, where do I get :> blueboard? Home Depot? Orchard Supply? :>

:> I have a lot of plaster type surfaces (walls and ceilings) that need :> repairs, and really need to figure out proper repair techniques. For :> instance, I have plaster falling down from ceilings from time to time! :> Any suggestions appreciated. :> :> Dan

[Tim Mulvey]

Dan, blueboard isn't the same as greenboard. They're both moisture resistant, but the paper of the blueboard is treated with a bonding agent to insure uniform and maximum adhesion to the board. If the paper becomes faded, it needs to be retreated. Use either a plaster bonding agent or an alum/water solution. 3 lbs alum to 1 gal water is the mix. You might be able to treat the whiteboard and the greenboard as well with this stuff. I've only used blueboard with plaster.

Tim

[Wayne Whitney]

No. Blueboard is blue, and as another poster mentioned, it is treated with alum to allow gypsum plaster to bond well with it. (Perhaps to allow the crystals to form through the paper?).

I don't believe either of them carry it, but the local building supply stores do, e.g. Truitt and White.

One thing to determine is whether it is actually the original plaster that is falling down. In my 1908 house in the same area, when the original plaster ceiling started to crack, someone added a skim coat of plaster/compound/whatever. It probably looked fine originally, but by the time I purchased the house it was falling off in pieces, and looked much worse that whatever original problem it was designed to cover. I ended up scraping it all off and repairing any cracks in the original plaster.

Cheers, Wayne

[DanG]

He could have used drywall compound. He was matching existing surface material, always a best practice. Another excellent suggestion would be to make the patch 4 inches larger than the hole both directions. Cut the paper on the back of the drywall 2 inches in from all edges and remove the drywall core leaving the finish paper attached. Generously mud the perimeter of the hole and wipe in teh patch. Small patches don't require a backer board, but they can be added easily. These patches tend to be stronger and easier to float in.

My

YOu can cap the existing plaster with a layer of drywall. Use screws and make sure you are fastening to the framing, not the wood lath. Finish as drywall or use Larsen's and skim plaster. Remember plaster is not DIY friendly.

Obviously, I can remove some (a LOT!)

I'm sure the original was applied well if it lasted 90 years, I'm afraid I probably won't. Vibration and dampness are anathema to plaster.

Removing all the finish plaster might

The easiest plaster product to work with is probably USG Structolite. It is a bit like Ragu - it's already in there. All you need is water. Another name to remember with plaster is Larsen's Plaster weld. Remember plaster has a learning curve. Plaster trowel and hawk have a learning curve. Metal lath is actually forgiving, but it will cut you in a heartbeat. Blue board and finish veneer plaster are not really like working with old wood lath and 3 coat plaster. Because of teh difficulties, many will recommend setting drywall compound for patch work.

I'm

[Dan_Musicant]

:The easiest plaster product to work with is probably USG :Structolite. It is a bit like Ragu - it's already in there. All :you need is water.

What's Ragu?

: Another name to remember with plaster is :Larsen's Plaster weld. Remember plaster has a learning curve. :Plaster trowel and hawk have a learning curve.

Watching Tom Silva work with blueboard and veneer plaster was a revelation. He's obviously a magician with it. I recorded the program and edited it down to a 10:27 segment and will keep it for reference. I've watched it a few times already and I'm sure it will help me in doing plaster work, at least veneer plaster work. Is veneer plaster a lot different from other plaster work? It seemed to be very smooth stuff, almost glassy after smoothing.

:Metal lath is :actually forgiving, but it will cut you in a heartbeat. Blue :board and finish veneer plaster are not really like working with :old wood lath and 3 coat plaster. Because of teh difficulties, :many will recommend setting drywall compound for patch work.

Drywall compound. Does it always come mixed or can you mix it yourself? I've seen big tubs of it, but don't remember seeing it dry.

The lath here is wood, and there's plenty of it, including the ceilings. Problem is, a lot of the plaster on the lath has suffered, probably because of the humidity in the house during the winter. I'm really going to have to learn techniques of repairing it. Putting drywall over it seems like a lot of trouble, but maybe that's what I should do, at least in places.

[Dan_Musicant]

:On 2006-07-23, Dan_Musicant wrote: : :> One particular wall problem in my old house looks good for this :> technique. I have a bunch of wallboard, some of it standard and some :> water resistant variety that was used to fix my bathroom. Would that :> water resistant variety qualify as blueboard? : :No. Blueboard is blue, and as another poster mentioned, it is treated :with alum to allow gypsum plaster to bond well with it. (Perhaps to :allow the crystals to form through the paper?).

Being color blind doesn't help here. I don't know what colors my wallboard material are. I guess I can get some alum and use it to be sure if I'm going to use veneer plaster over it. : :> If not, where do I get blueboard? Home Depot? Orchard Supply? : :I don't believe either of them carry it, but the local building supply :stores do, e.g. Truitt and White.

Thanks. : :> For instance, I have plaster falling down from ceilings from time to :> time! : :One thing to determine is whether it is actually the original plaster :that is falling down. In my 1908 house in the same area, when the :original plaster ceiling started to crack, someone added a skim coat :of plaster/compound/whatever. It probably looked fine originally, but :by the time I purchased the house it was falling off in pieces, and :looked much worse that whatever original problem it was designed to :cover. I ended up scraping it all off and repairing any cracks in the :original plaster. : :Cheers, Wayne

I think I may have the same problem in places - a faulty repair job on the ceiling. I think I'm going to have to scrape it all off, too. It will be a messy job. That's what dust masks, old clothes, tarps and shop vacs are for, and afterwards a good shower.

Dan

[George]

Thanks for that - I think it clears up a great mystery: I did some veneer plaster on blueboard some years ago. Mostly, it went OK; but, there were some spots (like 1 to 2" dia) where the plaster bubbled out, and just wouldn't bond to the board. This seems like a plausible explanation.

G

[Tasherra]

Well plaster is an art. If your not looking at the finshing of it then do it yourself. Considering the house is really old a few more repairs isn't going to hurt it none I suppose. Im in Canada and we have a product call con fill or confill. It has fiber in it and is great to fill large holes. It is very hard when it dries like cement and adheres to anything. Its great for ceilings cause unlike mud it won't drip or plaster your head so long as you make it with the right consistantcy. You would still have to patch the hole with any drywall. Usually board is in your old house 1/4 inch lath or 3/8 lath and when plastered it adds 1/8 to 1/4 of mud. Usually a 1/2 inch drywall will leave a perfect

1/8 inset compared to the surrounding plaster edge which is good. Patch it, make confill sort of thick or at least workable, this is not a finish so all you have to do is level it not be perfect. You can do this by using a strip of drywall and using the existing plaster as a guide, so just throw it all in there and compress it then use the strip to scrape it level then fill in the voids and to it again. Then get finshing compound and it will take three or in your case maybe 5 coats to make it nice for paint. sand first. Drywall supply stores would be the best place to find confill. it maybe a different name in your area but remember its got fiber in it.