So my FIL came over to help me extend an existing wall out in order to turn an open game room into an enclosed room with a door. I have no experience doing construction like this, but he's done it before.

Problem is after putting up the drywall, the new drywall is about 1/4" indented in from the existing wall. I was hoping for the new part of the wall to be exactly flush with the existing wall. We are at the stage where all the new drywall is up and screwed in and we've mudded the screw holes. Haven't touched the uneven joint yet where the new and old drywall meet.

Anyone have advice on possible options? I'm hoping at this point that maybe there is a way to gradually blend out this 1/4" difference somehow to where it's less noticeable than just an abrupt, uneven edge.

measure twice, cut once right?

maybe you could put up some kind of trim to cover it?

Isn't the edge of the new sheet of drywall beveled for a tape joint? I would expect it to be inset some just because of the joint bevel. A quarter inch seems a bit much but not all that unusual when you are matching new to old. You have to deal with the joint anyway so no big deal. I wouldn't think anything at all about what you described. Sounds like your FIL did well for you, keep going.

No, the edge isn't beveled. It's a quarter inch indented all the way across the drywall.

You're going to have to blend it about 2-3 ft out onto your new sheetrock & equidistant out on the existing. Sand down the high side a few feet back, do a big 4-6 ft mud smear and pack in the gap, dry, sand, mud again, dry, sand, repeat until there's no hump. It's time consuming but I've seen this a few times and when they're done, you'd never know there was a lip. A good sheetrock guy would take a full day to do it, even using quickset. Like mentioned above, you could scab it, too.

Would that blending work if the edge of the existing drywall was originally a corner and still has that metal corner bead underneath?

My original (completely uneducated) thought in all this was to think about slapping down a thick layer (could you do a 1/4" thick layer?) of the mud at the edge and then taper it gradually thinner for a few feet down the new wall. I'm guessing that's probably extremely difficult?

Take it out and buy thicker sheetrock like Sasappis said. The wall can't be that big. Cost 3-4 hours of work and $50 or so. Or you could pull it off and rip strips off 2x4s and attach to each stud and then rehang what you have. Personally I would start fresh.

I'm lost. Is this because you mismeasured during framing or because you used the wrong drywall thickness?

Either way, you will have to float the **** out of it. I'd use my 12" knife for this and hot mud. This will be a process and take a little doing but you are going to have to feather it across a long distance. It'll never be noticed.

If thus is because of the wrong drywall then I would stop while I was ahead and put the eight thickness in.

Feathering that out will take a metric **** ton of mud... I'd remove that corner bead, and rehang your existing rock over shims, or install thinner rock on top.

I ran into this on a shower redo in a condo I owned in school... just an 1/8 gap and I floated and sanded for a solid week!

Measured wrong with the framing I think. I wish we had stopped and corrected it by just getting a thicker drywall. After listening to y'all, I'm thinking it would be easier to try and put 1/4" drywall over the current stuff.

I'd be trying to correct this myself and sounds like the process of feathering this out with mud is way above my pay grade. I think I at least have a shot at the double drywall. The wall is only 5 feet long and 9 ft high. No electrical outlets or anything in the way.

One thing to remember... that corner bead sits about 1/8 inch high. It's already feathered out. Take it off then reevaluate.

I would remove the sheet rock, put shims on the studs and reinstall it. Cut the shims by ripping a 2x4 on your table saw.

Drywall on drywall is not how I'd fix it. Fur out the 2x4 and try again. Again..if I understand.

Sounds like older home with real 2x4s. Ran across this myself lately and luckily had some leftovers from a shed I tore down.

Depends how particular you are. I might just use several good coats of mud and level out. If high end home fix correctly by using above method of shims.

In situations like this one I've furred them out. It's not so bad, just make sure you have a helper for the table saw or make short (2') long pieces.

you could always sister the vertical 2x4s in the framing and just bring them out however much you needed.

Add me to the "take it down and fix it" crowd. Either shimming out the studs or sistering new studs at the right position will be much easier (and faster) than going back and trying to float out that big of a elevation difference. If you don't have a table saw to rip down a 2x4, you can also cut strips of 1/4" plywood with a circular saw or Home Depot sells drywall shims that are 1/16" thick cardstock that you can nail/screw/glue to the studs. You just stack as many as you need to get the level correct. Just make sure you're using long enough drywall screws to get through the shims and into the meat of the 2x4.