Go Back  DoItYourself.com Community Forums > Interior Improvement Center > Patching and Plastering
Reload this Page >

Need help replacing a section of drywall in the middle of a wall

Need help replacing a section of drywall in the middle of a wall

Reply

  #1  
Old 04-04-11, 04:50 PM
Member
Thread Starter
Join Date: Aug 2009
Location: New York
Posts: 240
Need help replacing a section of drywall in the middle of a wall

At my wife's request, we are giving one of our bathrooms a face lift.

One of the things we want to do is piece in a rectangular section of 1/2" drywall where a vanity was previously installed. I'm fairly handy, but to be honest, I have always had trouble finishing drywall and making seams and repairs look good. Though, I'm determined to fix this myself and become proficient with these kinds of repairs.

I need some help from the pro's here with the proper steps to follow in order to piece in a 18" x 14" section of drywall and make it look right. Especially since I'm not dealing with full sheets of new drywall with factory tapered edges.

I would appreciate any advise and guidance the members of this forum can give me.

Thank you.
 
Sponsored Links
  #2  
Old 04-04-11, 08:00 PM
Member
Join Date: Jul 2003
Location: California
Posts: 1,722
Cut the opening so the joint will be in about the middle between the studs. Cut 3/4" or 5/8" plywood about 5" wide and longer than the sides of the opening. Cut similar pieces to fit top and bottom Screw this plywood to each side of your opening so about half of the width projects into the hole and half is hidden and screwed to the existing wall. Cut the new piece about 3" larger than the hole in both dimensions. Cut the paper on the back side of the new piece to fit the opening. On the front leave a paper flange which will lap over the existing. Nextwith a sharp knife cut through the face paper on the existing about as wide as the flange and remove some layers of paper Screw the new piece to the plywood. Where the piece crosses a stud screw to the stud too. What you have done is used the flange to lap over the joint and recessed the existing wall edges to accommodate the flange thickness to make the patch flat with the wall -- no hump. Mix up some joint compound and smear it all around the edges and if there is a gap behind the flange fill it. Smooth the flange nice and flat. Let this dry and give it another coat of mud and lt it dry, sand, touch up any flaws, sand, texture to match if needed, prime and paint.
 
  #3  
Old 04-05-11, 04:13 AM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA
Posts: 43,834
I've used the above method a lot on smaller holes. The plywood will only work if there isn't a 2x4 above and below the cabinet opening. IMO cutting the drywall down the middle of the stud is too much work, I usually add a 2x to the existing stud and secure the drywall patch to it.

The biggest mistake diyers tend to make when finishing drywall is applying too much mud. You want just enough j/c to hold the tape [or paper edge if using the above method]. Multiple thin coats of j/c will make for a better looking finish..... and with less sanding I assume a mirror will go over the repair so you don't need a perfect job although the flatter/smoother it is, the better the mirror will hang.
 
  #4  
Old 04-05-11, 03:03 PM
Member
Thread Starter
Join Date: Aug 2009
Location: New York
Posts: 240
Tightcoat and marksr, thanks for the great suggestions.

In my particular situation, the cut out is between two existing studs so I'll attach a 2X to the studs on both sides of the opening so I'll have a good nailing surface. I'll also add narrow plywood strips on the top and bottom.

Thanks again for the help.
 
  #5  
Old 04-05-11, 04:48 PM
Member
Join Date: Jul 2003
Location: California
Posts: 1,722
Don't make the strips too narrow. You want a nice big target to screw to and to get the screws away from the very edge.

Something else I do is cut those cleats you are adding to the stud longer than the hole and screw them to the sheetrock on the top and bottom first then screw them to the stud. This will align everything better than cutting them the right length and nailing or screwing to the stud first and possibly misaligning them. You want everything to end up nice and flat and even.
I use a section of steel stud for a cleat. Lighter, easier to cut and handle 2 1/2" or 3" wide for a 2 X 4 stud. It's just easier to put in and gives a wider target to screw to than a 1X 2 and easier to screw onto the stud than a 2 x 2.
But that's just me. I am always looking for a better faster way to do this kind of patch.
It is almost as quick as the time it takes to type this.
 
  #6  
Old 04-30-11, 04:57 PM
Member
Thread Starter
Join Date: Aug 2009
Location: New York
Posts: 240
tightcoat and marksr,

I attached the framing pieces in the opening that the new piece of drywall will attach to. I've also prepared the new piece of drywall exactly as you described.

I have a question regarding making the paper flange on the new piece of drywall that I'm going to use to section in the wall. I made the flange but it took me forever using a dremel multitool once I outlined the opening size on the back of piece of drywall.

So I wanted to ask you both what's the fastest way to make the flange because the way I did it scraping off a little bit of the drywall material between the front and back pieces of paper was a huge job.

What's the secret. I worked with a plain utility knife and sharp blades but are there knifes with longer blades or special drywall tools that make the job easier?

Despite the time it took, hopefully the repair will look good.

Thanks.
 
  #7  
Old 04-30-11, 07:17 PM
Banned. Rule And/Or Policy Violation
Join Date: Oct 2010
Location: Canada
Posts: 448
Targa:

What I do is:

1. Use a drywall saw (which looks like a knife and has forward pointing teeth that cut on the push stroke) to cut out a rectange of drywall that extends to the studs on both sides of the hole. Cut parallel horizontal lines above and below the damaged area of drywall, and then cut the drywall flush with the sides of the studs on each side of the damaged area.



2. I cut two pieces of Spruce 2X2 lumber a little longer than the cutout hole is high. I predrill holes through the spruce cleats with an X-tra long 7/64 inch drill bit and an angle drill. (That drill bit is about 5 inches long, and you can get them at any place that sells fasteners and machine shop supplies.) Then, I countersink those holes in the cleats and use a Phillips #2 driver bit in the angle drill to fasten the cleats in place using 3 inch long drywall screws. (The conical countersink in the wood cleat accomodates the trumpet shaped head of the drywall screw well.)
It's best to use a REVERSIBLE variable speed angle drill so that you can also remove those 3" drywall screws.

3. Then I drywall screw the repair piece of drywall to the two 2X2's on each side of the cutout. (I agree that plywood cleats above and below would make for an even better repair.)

4. Then I use fiberglass mesh drywall joint tape over the joints, and fill in the joints with drywall mud. Some people say that paper tape is better. I say that paper tape is harder to get a decent looking job with. I've been repairing drywall and plaster for over 25 years now, and I use fiberglass mesh for every job I do simply because it works equally well and is less problematic.

Now, here are the secrets you were asking to know:

5. Where you don't have a contoured edge on both sides of the drywall, use a "curved trowel" available at most home centers and any place that sells Drywall and Plaster Supplies commercially.



Look closely at that trowel and notice that it arches upward about 1/8 of an inch in the middle. Since you hold the trowel at a comfortable angle to the wall when using it, a curved trowel allows you to spread a perfectly symmetrical "mound" of joint compound over your fiberglass mesh tape that's about 1/16 inch thick in the middle. That's plenty thick enough to bury fiberglass mesh tape in, but not thiick enough to create a visible "bump" on the wall, even if you have wall mounted light fixtures.

Also, the little bit of experience I have with premixed joint compound has convinced me that you need the arms and wrists of a mountain gorilla to spread that stuff smoothly. I expect the companies that make that stuff ship it so thick because no one wants to pay for the transportation of water, and you can always thin it yourself. Go to any place listed under "Small Appliance Repair" in your yellow pages and get some worn out kitchen mixer blades from out of their garbage can. Put a kitchen mixer blade in an electric drill, and use that to mix some water into your drywall mud so that YOU find it EASY to spread smooth. Do the mixing inside a cardboard box or plastic pail so that the spinning blade doesn't fling blobs of joint compound all over your house. And, of course, watch your fingers! You don't want to get them into that mixer blade when it's turning.

And, ALWAYS, ALWAYS, ALWAYS apply your joint compound and sand or scrape it smooth with a bright light shining at a sharp angle to the surface you're working on.



The critical lighting will make every trowel ridge look like a mountain range, but it'll give you a much better mental idea of where you need to add joint compound and where you need to remove it in order to achieve a smooth surface. And, once your repair looks OK under such critical lighting, it'll look perfect under normal lighting.

And, finally, don't SAND down each coat of joint compound you put on. It's much faster, easier and cleaner to simply hold your bright light near the repair and SCRAPE off any blobs or trowel ridges with a sharp paint scraper. The paint scraper will scrape off bigger particles of joint compound that fall straight down to the floor rather than hang in the air. Save the sanding for the final coat.

Hope this helps.
 

Last edited by Nestor; 04-30-11 at 07:37 PM.
  #8  
Old 05-01-11, 04:27 AM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA
Posts: 43,834
IMO it's a bad idea to cut away the drywall face paper and make a flange. Gypsum is very water soluble and can cause problems if wet j/c is applied directly to it although applying a solvent based primer first should alleviate that concern. SOP is to just float the joint out further.

The fiberglass sticky tape has a bad reputation! It is prone to failure when covered with regular joint compound. It's success rate is a lot better when a setting compound [like durabond] is used.
 
  #9  
Old 05-01-11, 08:08 AM
Member
Thread Starter
Join Date: Aug 2009
Location: New York
Posts: 240
marksr,

Now that I've invested the time to create the paper flange and cut away the paper on the existing wall to match it, should I just prime the cut away area on the existing wall and proceed?

Can I use Zinsser 123 to prime with or should I buy some actual oil based primer?

I guess I've learned alot by doing this project and will be prepared the next time.

Thanks
 
  #10  
Old 05-01-11, 09:53 PM
Member
Join Date: Jul 2003
Location: California
Posts: 1,722
I've done hundreds of patches the way I described. I always use setting compound. The reason for the flange and cutting off some of the paper on the existing is to get a flat patch. I suppose it's the plasterer in me but I hate to do a patch that is high or make joints that have to be feathered out way beyond the actual new piece to give the illusion of flatness. I want to lay by 6' rod across the patch and not be able to slip a dime between it and the wall along that length. Maybe it is not necessary to make a patch that flat in some cases. I can do it so I do.
You asked how to do it quickly. The way you cut drywall is to score one side, snap it back and cut the back side. The way to make a flange is to cut the back side of the new board then bend the edge back and peel the gypsum core back from the front paper.

As for gypsum being soft and soluble, if you use quick setting compound it bonds and sets before the core can soften and absorb the moisture from the compound.
 
  #11  
Old 05-02-11, 04:34 AM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA
Posts: 43,834
Originally Posted by targa View Post
marksr,
Can I use Zinsser 123 to prime with or should I buy some actual oil based primer?
An oil base primer would be better but if you follow tightcoat's instructions you can't go wrong, he is the expert!
 
  #12  
Old 05-02-11, 05:36 PM
Banned. Rule And/Or Policy Violation
Join Date: Oct 2010
Location: Canada
Posts: 448
Marksr:
Since when does fiberglass mesh drywall tape have a bad reputation? I've been using fiberglass mesh tape for over 20 years now, and no one told me that it doesn't work as well as paper tape. I guess I just never had any problems using the stuff, so I never took the time to seek out any better way. (Essentially the same material in a 10 inch wide format has been used for decades to repair leaks in flat roofs.)

Tightcoat:
So, you cut your drywall patch so there's a paper flap on the front that covers the gypsum core of the surrounding drywall. If I were to do that, I'd probably use some white wood glue to glue the flap to the underlying gypsum, although I can see that thinning some joint compound and using that would work reasonably well too. You'd still need to use tape of some sort over the seam between the drywall face papers.

PS: Congratulations to your US military for finally getting Bin Laden.
 
  #13  
Old 05-02-11, 08:19 PM
Member
Join Date: Jul 2003
Location: California
Posts: 1,722
Nestor,
In real life two things happen, First when you strip the core off the back side of the new piece of rock the paper tapers. Second, I don't take all the face paper off the surrounding area of the existing wall only some of the layers, and especially if it is there, the existing texture. So in essence the paper flap becomes the tape. I have not had a crack doing it this way for years. One thing I did not mention and should have is that the plywood nailers at the perimeters of the opening get a lot of screws, both onto the existing rock and the new piece. My idea is that the screws on the plywood is what holds the whole assembly together, thus the whole assembly moves as a unit not the patch independently of the existing which is what would be the source of a crack if there were one. One could forgo taking the face paper off and still have the flap act as joint tape the difference is it would not be flat.
I have used this method on patches as big as about 3' square. On anything larger I prefer to use the ButtTaper. (google it) With a lot of screws to hold everything together and with quick set joint compound I have omitted joint tape and still have no cracks. I tried all these methods in my own house years ago so I could keep an eye on them. They look as good as the day they were put on and I defy anyone to spot the patches, in one room even with glossy paint. I grew up plastering and have used some of what I know about plaster and plastering to perfect my drywall patches. I work for a couple home warranty companies and I work behind a couple plumbing firms and a roofer. I do a lot of patches.
 
  #14  
Old 05-03-11, 04:29 AM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA
Posts: 43,834
In the south, the sticky tape started to get a bad reputation within 6 months of it being introduced. The joints with sticky tape are bad to crack and or bulge. Using a couple of coats of setting compound over the sticky tape will usually prevent those issues. Regular ready mixed j/c over sticky tape just about insures failure.
 
  #15  
Old 05-21-11, 04:06 PM
Member
Thread Starter
Join Date: Aug 2009
Location: New York
Posts: 240
I just wanted to report back that I closely followed the procedure outlined by tightcoat along with advice by marksr and Nestor regarding primers and tools and the repair came out PERFECT.

I admittedly spent a lot of time on it because I wanted the repair to look good. But in all honesty, and considering I pieced in a section of drywall 14" by 40" in between the ceiling and the floor, you cannot tell where I repaired the wall.

Thanks everyone for your help, it was a great learning experience for me.
 
  #16  
Old 05-22-11, 03:49 AM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA
Posts: 43,834
Glad it worked out for you

ain't bragging rites great
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes