Hanging drywall in a Riverside garage conversion or room addition

By Drywall Contractor Riverside Raahi · October 6, 2026

Garage conversions, room additions and gutted bathrooms all end the same way: a framed space waiting for board. In Riverside, CA that usually means a 1960s or 70s tract house with a slab garage, a back porch or a bonus room that someone wants to make livable. Hanging drywall looks like the simple part of such a project. Sheets go up, seams get covered, and paint follows. In practice, the choices made in the first hour decide whether the walls stay flat and quiet for decades or telegraph every seam within two summers.

What does a drywall crew look at before hanging a single sheet?

The framing comes first. A crew sights down each wall and across each ceiling with a straightedge or a string line, looking for studs that bow, joists that twist and plates that sit proud of their neighbors. Board hung over crooked framing makes a crooked wall, and no amount of compound hides it for long. Small problems are fixed by planing a high stud or shimming a low one. Bigger ones are a conversation with the framer before any board is cut.

Next comes everything that hides behind the board. Electrical boxes should sit flush with the framing plus the thickness of the sheet, and plumbing and wiring need nail plates where they run close to the face of a stud. Insulation is inspected and cut tight around boxes. Once the board is on, anything that was missed becomes a hole cut into a finished wall.

Which board goes where?

Gypsum board is not one product. Half inch board is the common choice for walls in houses, five eighths board is stiffer and used where more fire resistance or sag resistance is wanted, and moisture resistant board and cement board belong in wet areas. The table below shows how a crew typically sorts the choices on a conversion or addition.

Code details vary by project and by the building department that signs off, so a crew confirms the requirement for a garage wall before ordering, not after.

How are the sheets hung?

Ceilings go first, so the wall boards can lift the ceiling edge tight. Sheets run perpendicular to the joists, and every end lands on a framing member so no joint floats. Walls are hung horizontally in most rooms because that puts a single long seam at a comfortable height instead of several short vertical ones. Seams from one row never line up with the row above, and the crew staggers them by at least a stud bay.

Fasteners matter more than most owners expect. Screws replaced nails for good reason: they pull the board tight to the framing and hold it there while the lumber dries and moves. Each one is driven just below the paper surface, without breaking through it. A screw that tears the paper holds nothing, and a screw left proud shows up under paint as a bump. Spacing is steady, and the crew skips the board edges when driving a screw close to the end of a sheet.

Why does the first coat take so long to get right?

Taping is the part that looks easy and is not. Paper tape is bedded in a layer of joint compound across each seam, then pressed flat with a taping knife so the excess squeezes out from under it. Too little compound under the tape leaves bubbles that show later as blisters. Too much leaves a thick ridge that takes a lot of sanding. Mesh tape is faster and acceptable for patches, though a long seam in a ceiling gets paper tape where strength matters most.

Inside corners are taped and creased, and outside corners get metal or paper faced corner bead, set straight and covered in compound. Screw heads each get a small dab. The first coat looks rough and ugly on purpose, since its only job is to fill and lock the tape in place.

What do the second and third coats do?

The second coat is wider than the first, spreading the edge out so the seam fades into the flat board. The third coat is wider again, and thin enough that a crew can feather it out to nothing. Between coats, the compound dries completely. In the dry air of the Inland Empire this can be quick, sometimes a few hours in summer, while a cool or damp week stretches the wait to overnight. Pushing the next coat onto damp mud traps moisture and causes cracks, bubbles and sanding that tears.

Sanding is done with a light hand. The aim is to knock down ridges without cutting through the compound into the paper, since exposed paper fuzzes up and shows through paint. A work light held flat against the wall, close to the surface, reveals the ridges and low spots that a ceiling fixture hides.

How does a garage conversion differ from a new addition?

A conversion works inside an existing shell, so the old slab, the old walls and the old garage door opening all have to be dealt with. The former door opening is framed in and boarded like any wall. The concrete floor usually stays, and board should stop above it with a small gap so it does not wick moisture from the slab. Many garages in older Riverside neighborhoods have no insulation at all, and walls that were once bare studs need the cavity filled before the board goes up.

An addition is different because the new wall joins an old one. Where the two meet, an old plaster or board surface has to line up with the new one, and the seam between them is a common place for a later crack, since the two sections of the house settle at different rates. A crew often tapes across the joint with paper tape and leaves a control joint where the geometry calls for one.

What about texture?

Most homes in the area carry a light knockdown or orange peel texture on walls and ceilings, and a new room that comes out smooth next to a textured hallway looks unfinished. Texture is sprayed after the final sanding and primer, then knocked down with a wide blade once the surface loses its wet shine. Matching an older texture takes a test patch on a scrap of board, because compound thickness and sprayer pressure change the pattern. Walls near windows get the smoothest finish, since daylight crossing them at a low angle exaggerates every flaw.

Frequently asked questions

How long does a small conversion take to board and finish?

Hanging goes quickly, often in a day or two for a single room. The finishing is what takes time, because three coats need three drying windows plus sanding and primer. A room that goes up in two days may need most of a week before it is ready for paint.

Can drywall be hung over old paneling or plaster?

Sometimes. Solid plaster in good condition can take a layer of thin board screwed through to the studs, though it changes the depth at doors and outlets. Wood paneling with grooves is usually removed, because the grooves telegraph through the new surface and the glue behind them can fail.

Why do new seams sometimes show after a year?

Almost always because of how the wall moved, not because of the finishing. Framing lumber dries and shrinks for its first year or two in a conditioned house, and a house near a fault line flexes with small tremors. A seam taped with paper tape and bedded properly resists this, while one with skimpy compound under the tape lets go first.

Is dust a problem during sanding?

It can be. A vacuum attached to the sander, plastic sheeting over doorways and a sealed return vent keep most of it out of the rest of the house. A crew that skips these steps leaves a fine white film on every surface.

Closing thought

Good drywall work is mostly patience: straight framing, tight board, thin coats and time between them. Skip any one of those and the walls tell on the crew within a season.