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How to Build a Basement Closet: Plywood Cap Installation

Bob Jackson
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by Bob Jackson

The plywood closet cap is installed in this update of How To Build a Basement Closet. This project is continued from Basement Closet Drywall Finishing.

Closet Light Electrical Permit Inspection

I filed for a building permit to cover the new electrical circuit for the closet light and left the 2×4 wall and closet ceiling open for the inspector to inspect the new wiring. The building inspector looked at the NM-B 14/2 wiring for proper installation, checked that all junction boxes – including the ceiling light octagon box – were grounded and the outlets correctly wired. (Note: The steel light switch box does not have to be grounded.) The building inspector confirmed NM-B cable is acceptable in Wiremold raceways so long as the outer insulation jacket is not removed. He said “Nice work!” and signed my permit for the final inspection.

Drywall Closure

I shutoff the electricity at the circuit breaker panel because I’ll be working with the closet light switch (a.k.a. toggle switch) as I measure for the drywall and mount the toggle switch to the box.

With the electrical inspection behind me, I can close up the closet by installing the final section of drywall. A drywall panel is cut from a 1/2 in by 4 ft by 10 ft sheet to fit around the closet door. This wastes most of the drywall sheet, however it’s best to install the largest section of drywall possible to minimize joints and achieve the best appearance. Click on the image for a full size view.

Building a Basement Closet: Drywall Panel Installation
Building a Basement Closet: Drywall Panel Installation

Since I’ve already wired the light switch, I’ll make careful measurements and mark the drywall for the switch box cutout. An alternate approach would be the “bump” method to make an imprint of the switch box on the back of the drywall as I did for the octagon ceiling box. However, in the interest of making productive use of my time while scheduling the building inspector appointment, I went ahead and wired the closet light circuit.

Remember the electricity has been shutoff at the circuit breaker.

Measuring the Switch Box for Fitting the Drywall
Measuring the Switch Box for Fitting the Drywall

The wired light switch was simply poked through the drywall cutout for the steel switch box (the circuit breaker is Off), then the drywall panel installed in the normal way with coarse thread drywall screws.

The last section of drywall after installation and finishing. The light switch won’t be mounted to the switch box until I’ve painted the drywall.

Basement Closet Construction: Drywall Installation
Basement Closet Construction: Drywall Installation

How to Build a Basement Closet: Plywood Cap Installation

Drywall or Plywood Closet Roof

I debated whether it would be best to install drywall or plywood for the closet cap (or roof it you prefer). The 2×4 closet ceiling joists are load bearing and can support a substantial weight, including my 215 lb frame without so much as a creak or wobble.

If I capped the closet with 1/2 inch drywall, I thought it would only be a matter of time before someone (perhaps a future homeowner) either climbed on top of the closet or used it for extra storage space and broke through the drywall.

Plywood Closet Roof

I decided to install 1/2 inch cabinet grade plywood for the closet roof for strength and durability. I can now use the space over the closet for extra storage or work platform should I ever need to install an access panel in the suspended drywall ceiling to get at crawlspace. (I can’t image why I’d ever need to work in the crawlspace 😉 maybe to fix a plumbing problem or run new wiring.)

The 1/2 in by 4 ft by 8 ft sheet of cabinet grade plywood is set on the closet to mark the dimensions for sawing. This was easy, I just ran a pencil along the edge of the drywall.

Basement Closet Construction: 1/2 inch Plywood Cap
Basement Closet Construction: 1/2 inch Plywood Cap

I made the first cut with my circular saw by:

  • Laid the plywood on 2x4s for clearance over the concrete floor.
  • Clamped an aluminum channel as a saw guide to the plywood sheet.
    The aluminum channel must be setback from the pencil line to align the saw blade with the line.
  • Adjusted the saw blade depth to about 3/4 inches so it’s well clear of the floor.
  • Rechecked alignments, floor clearance and any obstructions, then made the saw cut.
Building a Basement Closet: Sawing the Plywood Cap
Building a Basement Closet: Sawing the Plywood Cap

The second circular saw cut is made the same way. Notice the offset between the aluminum saw guide and the cut edge so the blade is aligned with the pencil line.

Building a Basement Closet: Plywood Cap 2nd Cut
Building a Basement Closet: Plywood Cap 2nd Cut

A really neat thing is the saw dust vacuums off SkimStone concrete floor very cleanly.

The 1/2 inch plywood closet cap ready for installation:

Building a Basement Closet: Plywood Cap Ready to Install
Building a Basement Closet: Plywood Cap Ready to Install

The plywood cap is set on top of the closet for fastening with wood screws:

Basement Closet Construction: 1/2
Basement Closet Construction: 1/2″ Plywood Cap

I made small pencil marks on the wall for the centers of the 2×4 ceiling joists then drew a straight line with the 4 foot level to locate the joists. I also made careful note of where the NM-B 14/2 cable was run through the bore holes in the 2×4 joists so as not to set a wood screw into the cable. The 2 inch bugle head deck screws were driven in a regular pattern and set even with the plywood surface.

Building a Basement Closet: Plywood Cap Mounted with Wood Screws
Building a Basement Closet: Plywood Cap Mounted with Wood Screws

Outside Corner Moulding Installation

Outside corner moulding purchased at the local home improvement store is installed to cover the edge of the plywood cap and drywall. I measured and made the 45 degree miter cut on my Dewalt Compound Miter saw:

Outside Corner Moulding: Miter Cut
Outside Corner Moulding: Miter Cut

The outside corner moulding is fastened to the edge of the closet wall with 1-1/2 inch brad nails set in the side and top. The brad nailer is a wonderful tool!

Outside Corner Moulding: Fastening with Brad Nails
Outside Corner Moulding: Fastening with Brad Nails

Outside corner moulding and the 45 degree corner miter cut as viewed from above the closet:

Closet Outside Corner Moulding: Top View
Closet Outside Corner Moulding: Top View

Trimming out the closet walls with outside corner moulding will look really nice when painted:

Basement Closet: Outside Corner Moulding
Basement Closet: Outside Corner Moulding

The plywood cap deck screws and wall joints are filled with paintable silicone caulk:

Basement Closet Construction: Plywood Cap and Outside Corner Moulding
Basement Closet Construction: Plywood Cap and Outside Corner Moulding

Now that the drywall is finished, I can install the door jambs, door casing and bi-fold doors in the next project update.

Take care,

Bob Jackson

2x4 ceiling joistbuilding inspectorbuilding permitcloset light switchdrywall finishing
Bob Jackson
Bob Jackson
Technology product manager by day and a prolific handyman in the evenings and over the weekends. Bob was the founder of the original Handyman How To website and that tradition continues on this site with excellent new handyman content into the future.
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