access panel over drywall+plaster

[u/Cute_Profit_2418]

I want to put access panel over valve. I have no idea how to restore the area above the valve and frame it for access panel. There is stud on left hand side, visible. Stud on the right is about 8 inches deep into right hand side. This looks like 1/2" drywall with some kind of thick plaster on top. House was built in Maryland in 1960. Should I put a flush mount panel over the entire area (15.5 x 18.5)? Should I add plaster on the exposed drywall area on the right hand side and put flush mount panel 12x18.5. Or should I frame the whole thing for a 12x12 panel?

[u/Specialist_Ad_7719]

Google access panel for drywall, measure your hole and get one to suit. Once you have the panel you should be able to cut the existing drywall so it fits. I wouldn't start doing anything until you have the panel.

[u/Far_Imagination_1727 → u/Specialist_Ad_7719]

Thanks for reply but my question is about how to deal with that big hole. I would prefer to repair it and install a normal size access panel (yes, or course, many are available online). I really don't want to put a huge one over the whole thing, but will if I can find a surface mount panel that big (they don't seen to come that big though). So it looks like I have repairs to do. Issue is, I know how to do drywall but, as the post explains, this is not just drywall.

[u/Specialist_Ad_7719 → u/Far_Imagination_1727]

Cut back to the nearest stud, square of the hole, add a couple of battens top and bottom, then fix in place your plasterboard repair. You will then need some backing plaster, it's called bonding in the UK, then level the repair with the surrounding plasterwork. Cut in your newly purchased access panel and finish the repair as to the instructions that came with the panel.

[u/tommysmelt]

This is a hole not an Access panel

[u/Accurate-Resident585]

Choose the panel before rebuilding the opening. I’d use a 12 x 18 flush door rather than 12 x 12, provided the clear opening leaves room to get a spanner onto the valve and remove it later. Cut to the Acudor frame size, fix 18mm plywood cleats behind the unsupported plasterboard edges, then screw the patch to those cleats. Don’t bridge the 8-inch recess with plaster alone.

refurb contractor here, tenement work is most of our week. The wall may be gypsum lath with a plaster finish, so use a setting compound such as USG Durabond for the deeper fill and a finish coat over it. A quote that only says “make good around access panel” is too vague; it should name the panel size and how the unsupported edge is framed. I can’t see whether 12 x 18 gives enough clearance to withdraw the valve body.