Matching plywood to sheetrock

[fishhead]

I'm replacing the wall covering in my bedroom and I'd like to strengthen the corner by putting a sheet of 1/2" BC plywood on each side of the corner.

Could I then just butt the 1/2" sheetrock up to the edge of the plywood and do the normal taping?

[Katey]

They aren't going to be the same thickness. Plywood doesn't come in true 1/2" any more. What are you trying to accomplish by strengthening the corner?

[Riverdale]

You could, if you are handy with a tape knife

[Dead Rabbit]

they are close enuff to match, once you float it out with your mud. but even the BC isnt as smooth a finish as the drywall board.

im curious....like KATEY said, what are you trying to accomplish

[Sawmill Jim]

They make metal or plastic bead corners that work well unless you are running a forklift in the house

[TnAndy]

Originally Posted by Katey

They aren't going to be the same thickness. Plywood doesn't come in true 1/2" any more. What are you trying to accomplish by strengthening the corner?

Neither, apparently, does sheetrock. We did some remodeling to our house and the 1/2" of today is apparently thinner than the 1/2" of 1985.

My question on the plywood is how do you plan to finish the surface of the plywood to look like sheetrock ?? You're gonna have one smooth, paintable surface next to a rough surface that will never paint up to match.

[fishhead]

My reason for wanting to strengthen the corner is last fall when I temporarily removed the masonite siding to put up 1" foamboard on the outside of the house the box car siding underneath had some really bad dry rot and carpenter ant damage. I'm almost expecting to find some bad studs when I remove the buffalo board. Since the box car siding isn't providing any sideways strength I thought I would put plywood in the corner. I've seen it put on the outside corners on previous construction jobs I've had.

My other option is to cut some diagonal 1"x4" boards so they are flush with the stud. That would be cheaper and pretty effective.

The plywood I would use would be BC so the surface should be pretty smooth.

[Dead Rabbit]

i guess you could skim coat the BC...that may work. ive skim coated small sections of trim board before, but never plywood.

[Dead Rabbit]

Originally Posted by fishhead

My reason for wanting to strengthen the corner is last fall when I temporarily removed the masonite siding to put up 1" foamboard on the outside of the house the box car siding underneath had some really bad dry rot and carpenter ant damage. I'm almost expecting to find some bad studs when I remove the buffalo board. Since the box car siding isn't providing any sideways strength I thought I would put plywood in the corner. I've seen it put on the outside corners on previous construction jobs I've had.

My other option is to cut some diagonal 1"x4" boards so they are flush with the stud. That would be cheaper and pretty effective.

The plywood I would use would be BC so the surface should be pretty smooth.

they make long metal straps that are meant to be installed diagnally in corners. do the same job as plywood. it was a practice back in the 80's i believe. you dont see it now, but code wont allow here either. same idea as the 2X4 you mentioned but lot easier w/o the notching and all that.

another option i practice quite a bit. i glue the drywall to every stud than use drywall screw. that glued on drywall is unbelievably strong. helps with nail pops and such.

[fishhead]

What do you use for glue? It would have to stick to my plastic vapor barrier.

I'll check on the straps. That would save a lot of dinking around.

[Sawmill Jim]

We used a plastic wrap on a house once were telling the owner he was getting it to tight . He did it anyway it sweated the closets an moisture became a real problematic . He did walls ceilings and all a house has to breath . Just a thought

[fishhead]

This house breaths better than I do. I had a shrew living in my house until the neighbors cat caught him outside recently. I've even seen chipmunks in my living room.

In this climate if you don't have a vapor barrier your walls will fill with frost and rot. I think that's what happened to the wall.

[Explorer]

Originally Posted by fishhead

What do you use for glue? It would have to stick to my plastic vapor barrier.

I'll check on the straps. That would save a lot of dinking around.

The straps do not provide any compression strength. Use inset 1x4 diagonally and they provide the same function as a plywood shear panel.

[Dead Rabbit]

glue....any type of construction adhesive. ie. liquid nails

you dont want any vapor barrier on inside of house under sheetrock. its not allowed by code here either.

vapor barrier, or a house wrap is used on exterior.

[Dead Rabbit]

Originally Posted by Explorer

The straps do not provide any compression strength. Use inset 1x4 diagonally and they provide the same function as a plywood shear panel.

can you explain the compression strength to me?

[fishhead]

Our code must be the opposite because here it goes under the sheetrock so that migrating moisture is not allowed to reach the insulation. Without that barrier moisture migrates outward and when it hits the cold insulation it forms frost and ice.

I see people using breathable house wrap here to stop the wind.

I've seen what migrating moisture can do when I had big fish tanks in the basement. It hit the cold and froze. So much accumulated that it bowed the siding out 4-5" and then dripped down the outside of the siding. My siding is still bowed from that.

We're already at highs of teens or 20's and within 30 days we'll probably hit -20 or colder at night. In those temps you can't let the moisture reach the cold.

I'll check on those straps. I should be able to use tensile strength in both directions if I put a second strap going from the bottom to the top as it goes away from the corner.

Tensile strength is what you get when you pull things apart. Compressive strength is when you try to compress things. Steel is good at tensile and wood is good at compression.

[Sawmill Jim]

This was on the inside of the rooms they put the plastic right after the insulation before the wall board not on the outside of the house . Think he warped it too .

We get 20 below you will see a vapor trail it'll be me leaving

[TnAndy]

Originally Posted by Dead Rabbit

glue....any type of construction adhesive. ie. liquid nails

you dont want any vapor barrier on inside of house under sheetrock. its not allowed by code here either.

vapor barrier, or a house wrap is used on exterior.

Nope....recheck your code. Vapor barrier ALWAYS goes on the warm side.

House wrap is a barrier to air infiltration, but not moisture. You wrap the outside of a house in a true vapor barrier, and you'll rot the walls inside. Moisture moves thru a wall ( or sheetrock ) to the point of the vapor barrier, then stops. Putting it on the outside will cause your insulation to stay damp, and promote rot.

[TnAndy]

Originally Posted by fishhead

I'll check on those straps. I should be able to use tensile strength in both directions if I put a second strap going from the bottom to the top as it goes away from the corner.

Yep...that's how they work.....you put one in both directions from the top of the corner to the bottom of the shoe plate. Have to be used in pairs, or you only have strength in one direction.

[Dead Rabbit]

yup yall are right. i shouldnt have said vapor barrier on outside. im wrong. it was common practice in past to put vapor barrier on inside over insulation. they stopped that. house wrap is outside. and is required now.

i understand compression strength but i dont understand why its used in conjunction to framing.