Is this drywall still usable with a skim coat & prime, or I need new one?

lifan

Howdy all,

First post on the DIY forum... We just bought a house (yey!) It's about 30 years old, the bedroom is covered with outdated wallpaper, we are planning on remove all wallpaper and put on some good quality paint. After tearing half of the wall in one bedroom, I find that there are plenty mildew growing there, and some of the top surface of drywall got peeled off with wallpaper.





Previous owner apparently just taped tearing wallpaper using packing tape and left the mildew problem there untreated...

Can I just skim coat the old drywall with dry wall compound and prime it to seal what's under and then paint, or do I need to actually tear the old drywall and install a new one? (I'm a novice at home improvement and never installed any drywall before.)

Is it necessary to kill the mold first (with a good sponge&wipe with bleach and water mix) or can I just skim coat it directly without worrying the mold?

(Tested for lead and the drywall is leadfree.)

Thanks for your help!

joecaption

You could just kill the mold and skim coat it but it would not address why it's molding up.
You have one of several possible things going on behind that wall.
If it was mine I'd be removing all the dry wall under the window to see if it's the window leaking from outside, poor or no insulation, condinsation because the windows only single pane and the house is to moist ECT.

lifan

Thanks for the advise Joe, I noticed there are some gaps between the drywall and window. Maybe sealing these holes will fix the prob? Would a silicon/latex sealant work here?

joecaption

Sealing them will do nothing but seal in the moisture behind the wall.

sdsester

I agree you should figure out where the mold/mildew is coming from and you probably have to open up the wall space under the windows to find the source. It will not cost you that much to replace the drywall sections. It may be that the mold was just growing in the paste but best be sure.

Assuming the rest of the drywall is alright, you can get as much paste residue off as you possibly can than prime with Gardz. Patch and skim coat as needed. Prime the patches and apply two coats of paint.

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Maintenance 6

What you are finding is not all that unusual. I've seen it many times. The vinyl wallpaper traps some moisture behind it, especially around windows and doors where the temperature changes and allows some small amount of condensation to form. Wallpaper paste is gourmet mold food, so mold colonies easily develope in that area. Remove the paper, do a light scrub down with a 10% bleach solution and let that dry. Then prime with a stainblocker and paint. Most likely, without the wallpaper trapping the moisture, you will never see a reoccurance.

drywallfinisher

why fear replacing a ruined wall? that makes no sense to me. the area is relatively small. remove the board, look at what's behind it, bleach it, let dry, rehang and finish the two joint the are short and beneath a window...just replace it