Plaster-in vents
A plaster-in vent, which drywall contractors call a mud-in vent, has a thin perforated rim that is finished into the wall or ceiling with joint compound (mud) or plaster, so the vent sits flush with the surface and only the opening shows. HiFi's patent-pending plaster-in vents connect directly to round duct, fit an existing register boot, or connect to a small-duct high-velocity system. For the look, and how plaster-in compares with other flush vents, see the trimless vent guide.
The rim
The rim is what makes a vent plaster-in. It is a thin, perforated flange around the opening that sits against the drywall or plaster. Mud or plaster goes over it, keys through the perforations, and is feathered into the surface around it, so after paint the room sees the opening and no edge.
Pick the lip height for the finish: 1/16 inch for joint compound (mud), 1/8 inch for plaster. A plaster coat builds up thicker than a skim of mud, so the plaster lip stands taller.
Three kinds
Behind the rim, a HiFi plaster-in vent takes one of three forms.
- Direct-connect. A body that connects straight to 4, 5 or 6-inch round duct, with no register box or boot: round faces, 4x4, 6x2 and 8x2 faces, a removable linear vent and a 12-inch linear slot.
- Register faces. A plaster-in face for an existing square or rectangular register boot, in catalog sizes from 6x4 and 10x3 to 30x20. Full plaster-in faces are fixed, and the finish runs across the face so only the openings show. Removable faces have a grille that lifts out for cleaning, set flush or inset.
- High-velocity outlets. 2-inch round, square and hexagon outlets and 6 and 12-inch linear outlets for small-duct high-velocity systems. See the high-velocity outlet guide.
Shop traditional HVAC vents for the first two, and high-velocity outlets for the third. Outside the catalog, any shape, size, pattern or duct connection is made to fit the job: tell us what you need.
Installation
The installation guides and videos are grouped by product family. In outline:
- Choose the path. Rough-in goes in before the wall or ceiling is closed. Push-through goes in through a hole cut in a finished surface.
- Mount the vent. Hold the frame flush to the board with drywall screws, spray adhesive, or cyanoacrylate glue and activator. Models with mounting holes take pan-head or cabinet screws.
- Connect and seal. Seal the joints to the duct with foil tape.
- Mud in the rim. Finish over it with joint compound or plaster, feathered into the surrounding surface.
- Prime and paint. Where the model is meant to be painted, use a high-quality bonding primer.
Keep the air slots clear at each step. On a removable model, finish the fixed frame and keep compound and paint out of the grille's seam.
Choosing one
Start with the system on the drawings, conventional ducted or high-velocity, since the two take different connections. Then choose the connection (round duct diameter, register boot size, or high-velocity connection), the stage of the job (rough-in or push-through), and the face (a plain opening or one of HiFi's proprietary patterns, fixed or removable).
Find your vent narrows the family in a few questions, and the product page confirms the model. Browse the whole catalog, and see room ideas in the lookbook.
To see the detail before specifying a larger job, start with a single unit from the catalog. Hold it, mount it, or show a client.
Airflow
The finish changes the edge of the vent, and the air still has to get through. Each room's airflow comes from the load calculation (ACCA Manual J) and the duct design (ACCA Manual D); the project's mechanical designer sets the target for each location, and the vent is chosen to deliver it.
Our linear direct-connect and linear high-velocity families have internal flow paths formed in the body; geometry varies by model. For the figures we have from our CFD models, see the high-velocity outlet guide, or send us the model you plan to specify and we'll send the airflow and pressure-drop information we have for it.
Ordering
HiFi offers a standard catalog of sizes and patterns, along with custom options for project-specific requirements. Orders typically ship within 2-3 weeks. Rush orders are available if your schedule is tight.
HiFi's patent-pending design and manufacturing process can make any shape, size, pattern or duct connection to fit the job. For a whole house or building, send us your list in any format: a spreadsheet, a page from the drawings or a photo of your notes. We'll match each vent to the catalog, confirm it with you, and send one invoice.
Questions
Is a mud-in vent the same as a plaster-in vent?
Yes. Mud-in is the drywall trade's name for the same detail: the perforated rim is bedded in joint compound, which finishers call mud, and feathered out. Plaster-in also covers plaster finishes. Either way, only the opening shows once the wall is painted.
Should the air slots be plastered over?
No. Keep the air openings clear of mud and plaster. On a full plaster-in face the finish continues across the solid face but must not fill the slots. On a removable model, finish the fixed frame and keep the grille's seam free.
Do plaster-in vents work with drywall, or only plaster?
Both. HiFi plaster-in vents install on drywall or plaster walls and ceilings, and the rim is finished with joint compound or plaster. Pick the lip height for the finish: 1/16 inch for joint compound (mud), 1/8 inch for plaster.
Can a plaster-in vent fit my existing register boot?
Yes. HiFi's register faces fit into a square or rectangular register box or boot, with the perforated rim overlapping the drywall or plaster around it. Measure the box before ordering. Catalog sizes run from 6x4 and 10x3 to 30x20, and any other size is made to fit.
Can I put a plaster-in vent in the ceiling?
Yes. They are made for walls and ceilings. With a round removable model in a ceiling, the body mounts above the board, the rim is buried in the finish, and the removable face stays accessible from below.
How do I clean a plaster-in vent?
On a removable model, lift the grille out, clean it and set it back. A full plaster-in face stays in place, so clean it where it is and keep the openings clear. If you are unsure about a cleaning product, ask us before using it.