How to Install Glue-Down Carpet

On the floor it was one job. This is the direct-glue method — carpet bonded straight to the subfloor — and it is a different trade from stretch-in, which this store is honest about not tooling; that distinction is the first thing below. Sibling to *Install sheet vinyl* and *Install linoleum*; the seam-edge cutting belongs to *Seam two pieces of carpet*, and this guide is the adhesive side that guide hands off to.

Job: bond broadloom carpet directly to a prepared subfloor with troweled adhesive — cut to fit, spread, laid into the bed, rolled, seamed, and trimmed to the walls.

Time: one open room over a sound, prepped subfloor is a day — and, as with every resilient floor, the cutting is minutes of it; subfloor prep, the adhesive's open time, and rolling own the clock. A slab that needs a moisture verdict, patching, or an old floor taken up first adds a day — or a lab wait — before this one starts.

Difficulty: moderate, with two places it is won or lost — the adhesive's open/flash window and the seam. The cuts are learnable in an afternoon; timing the lay-in to the right tack and closing an invisible seam into a wet bed are the skills. Honest first-timer scope: a basement or closet-sized room, goods wide enough to skip the seam — or hire the seam, and this page says so without embarrassment.

The tools from this catalog:

19062 MAXXGRIP® 1/16" x 1/16" x 1/16" square-notch adhesive trowel — the workhorse carpet meter. Hyde's duty line names carpet, and the fine square lays the continuous grabbing film that standard commercial broadloom wants, on a soft-grip, riveted-aluminum-spine body built to spread a whole field by the gallon.

20550 Black & Silver® Flooring/Roofing Knife — the heavy hand: stiff commercial backing, doubled seam overlaps, and any tear-out of the old floor first.

The notch caveat, first and loudest: the notch is the adhesive label's call, never this page's and never the truck's. These are the line's *carpet-duty* meters — the tools Hyde built for the trade — but a glue-down carpet adhesive names its own trowel, and that number outranks everything here. Match the meter to the pail.

Everything else (the store doesn't sell these — stated plainly, because that's the moat):

the carpet or adhesive maker's specified glue-down adhesive — and its primer where the label calls for one (bare, porous, or dusty slabs usually do); the label owns the adhesive, the notch, the open time, and the coverage, and it outranks every word here

a carpet roller — a weighted push roller, or a rented 75-to-100-lb three-section floor roller; a glue-down floor is not bonded until it's rolled, and this catalog doesn't carry one

latex seam sealer for the cut seam edges and a hand seam roller — neither on this shelf; skipping the sealer is how a glue-down seam frays (the seam is treated honestly below)

for stretch-in instead of glue-down: pad, tackless (tack) strip, a knee kicker, a power stretcher, and a stair tool — none of them here, because this store tools the glue-down trade, not the stretch trade (the honest distinction, Step 1)

steel straightedge · chalk line and marker · a row-finder or blunt awl for loop goods · tape measure and pencil · a slab moisture and pH test (a taped-down poly square overnight at minimum; calcium-chloride or in-situ-RH probe and a pH pencil where the label demands) · portland-based floor patch for the lows · a sacrificial surface for the rough cuts (garage slab, a sheet of OSB) · knee pads ([09086], drywall-installation line — the carpet layer is the subject population of the NIOSH knee alert, told in full over there) · the exact cleaner the adhesive label names, for the squeeze-out you clean now · a sharps container for spent blades if a replaceable-blade carpet knife is on the job.

Before you start: pick the trade, clear the old floor, then read the slab

Glue-down or stretch-in? Decide the trade, because they share almost no tools. Stretch-in is the residential default: a separate cushion (pad), tackless strip pinned around the room's perimeter, and the carpet stretched drum-tight over the pad with a power stretcher and a knee kicker and hooked onto the strip's angled pins — a floor that floats on cushion and is held only at its edges. This store tools none of that. Glue-down (direct-glue) deletes all of it: the carpet is troweled straight to the subfloor with adhesive — no pad, no strip, no stretch. Its home is commercial floors, basements, slabs-on-grade, ramps, and anywhere rolling loads (chairs, carts, wheelchairs) would ripple a stretched floor over pad, or a bare slab offers nothing to nail a tack strip into. The honest, saleable line: this store sells the glue-down kit — the notched trowel and the flooring knives — and is candid that the stretcher and kicker are somebody else's aisle. (A commercial double-glue variant — pad glued down, then carpet glued to the pad — exists; it is two glue-down passes and is out of this direct-glue page's scope.)

The short version stands on this page too: pre-1980s vinyl-asbestos and asphalt tile, the felt backing under old sheet goods, and the black "cutback" adhesive beneath them can contain asbestos; you cannot identify it by eye, a lab can, and a tear-out — strip-cutting, scraping, snapping — is the exact disturbance that puts fibers in the air. Treat a suspect floor in a suspect-age building as asbestos-containing and have it sampled before any tool touches it (EPA — Protect Your Family from Exposures to Asbestos). Glue-down demands a clean, sound, flat substrate, so most jobs mean removal — which means Step 1 over there comes first. Old adhesive left on a slab from a previous floor is its own guide, *Remove floor adhesive and mastic*.

Flat, clean, dry — the substrate decides the bond. Glue-down both telegraphs the subfloor and bonds *to* it, so flatness and cleanliness are load-bearing, not cosmetic. Fill lows and grind highs to the flatness the carpet and adhesive spec name (commercial specs commonly call a tight tolerance over a measured span); then vacuum to a clean-room standard, because dust is a bond-breaker under adhesive — a spread laid over a dusty slab grabs the dust, not the concrete. And get the slab dry: glue-down lives on concrete more than any other resilient floor, and a slab passes moisture and alkalinity upward. Test to the adhesive label's number — a poly square taped down overnight at minimum, a calcium-chloride or in-situ-RH test and a pH read where the label requires — because a slab wet or alkaline enough will let a picture-perfect glue-down blanch and release months later. Prime the slab where the label calls for a primer; porous or chalky concrete usually does, and the primer is the label's call, never this page's.

Layout: nap one way, seams placed, then dry-fit. Roll the goods out and plan before a drop of adhesive. Nap discipline is absolute — every piece lays with the pile leaning the same direction; reversed pile reads as a color change in every light and no adhesive fixes it. Sweep the pile with your palm, mark a nap arrow on the backing of every piece, and never rotate one 180° to save material. Place the seams the way the seam guide teaches: run them *toward* the room's main window (light traveling *along* a seam hides it; light *across* it shadows every gap), out of doorways and pivot traffic, and biased toward where furniture will sit. Pattern goods match at the repeat and cost material for it. Then dry-fit: rough-cut pieces laid in place, seams overlapped an inch or two, everything squared to the room's long sightline. Full-spread adhesive is a one-way door — this is the last cheap minute of the job.

The cutting side: rough-cut from the back

Rough-cut oversize, from the back, on a sacrificial surface. Carpet is cut from the back, not the face: flip the piece pile-down, strike the cut line on the backing with a chalk line or straightedge, and pull the flooring knife through the backing — pierce with the point, lay the blade into the draw, and pull toward you so the curved edge feeds the stiff scrim into the cut instead of letting it climb off the tip. Cut every piece a few inches oversize; you trim it to the wall in place later (Step 12). The 20200 leads for standard broadloom; on heavy commercial backing — stiff woven goods or a hard actionback that folds a lighter blade — the 20550 earns its tier: the .072" blade takes the punch-through without flexing, and its hollow grind is the specific cure for backing that clamps a flat blade's cheeks mid-pull. Keep the blade vertical on any edge that will become a seam — a leaned blade hides a bevel that meets at the face before it meets at the backing, and that is a visible seam waiting to happen. Carpet backing is stiff latex-filled scrim that dulls steel far faster than the soft pile suggests, and a dull blade tears backing instead of severing it, exactly where a seam will show — stone the hawkbill or run a fresh edge before seam work (*Keep a carpet knife cutting* / *Sharpen and maintain a flooring knife*). The detailed seam-edge method — conjugate trace-cuts and the true double-cut — is *Seam two pieces of carpet*'s job; cut your field pieces here, cut your seam edges there.

The adhesive side: spread the bed

Fold back, read the pail, pick the meter. Fold a fitted half of the room back on itself without creasing it, and read the adhesive label for its trowel. The store's carpet-duty meters are the 19062's 1/16" square — the workhorse for standard commercial broadloom, laying a continuous grabbing film — and the 19040's fine double-U for lighter or thinner goods and adhesives that want a leaner bed. Read them honestly: a heavy secondary-backed or woven carpet, or a double-glue system, can name a coarser notch than either of these fine meters carries — and when it does, the label wins and you buy to it. The notch is a meter; the label set the dose.

Spread it right — the two laws that don't bend. Hold a consistent blade angle (roughly 45°; flatter under-meters, steeper over-meters — correct the angle before you blame the notch) and comb straight ridges in one direction, never swirled. Parallel ridges collapse under the carpet and vent their air out the open ends of the channels; swirled ridges seal air into closed loops, and every closed loop is a bubble with a schedule. Two more laws from the line: the notch meters a bond, not a topography — you flattened the slab in Step 3, so never spread thick to bridge a low spot — and never change meters mid-floor, because two different beds under one carpet is a bond defect by definition. The 19040's four edges pay off here in a real way: carpet adhesive is gummy, and when one edge loads up and starts dragging you rotate the trowel to a clean edge and keep the meter true instead of stopping to scrape.

Open time, and the wet-vs-tacky call — the skill of the job. Every glue-down adhesive has a window between spreading and laying, and the label owns the number. Two families run two rhythms. Wet-set adhesives take the carpet almost immediately into a still-wet bed — fast, but a wet bed can bleed up into the pile and let the carpet slide. Tacky-set / pressure-sensitive adhesives are spread and allowed to flash to a specific tack — dry enough not to bleed, sticky enough to grab — before the carpet goes down. Your fingertip reads the tack the label describes; the clock moves with temperature, humidity, and how porous the slab is. Down too early into a too-wet bed and the carpet floats, bleeds, and slides at the seams; down too late after the bed skins and the bond is starved — it holds today and lets go by spring. Spread only what you can lay and roll inside the window.

Lay in, roll, and seam

Lay the carpet into the bed. Roll the folded half down into the adhesive from the fold line outward — lay it *in*, don't drop it flat and trap a ridge of air beneath it. Set the seam edge and the pattern to their lines as the carpet meets the bed; you have until the adhesive grabs to nudge it true. Then fold back and spread the room's other half and lay it the same way.

Roll it — the step that makes it a bonded floor. Roll the whole field with a carpet roller (or the rented 75-to-100-lb three-section roller), from the center outward in both directions, overlapping every pass. On wet-set goods, roll again near the end of the open time as the bond pulls in.

Close the seam into the wet bed — and the honest hand-off. Glue-down seams skip the hot-melt tape-and-iron system entirely: there is no seaming iron in a direct-glue seam, and none in this store. That seam guide cuts the edges and hands the adhesive side to this one — this is exactly where it lands.

The cutting side again: trim to the walls

Trim the perimeter with the point. With the carpet bonded, press it hard into the wall-floor junction to crease it, then run the 20200's long point along the crease — the spine leaned into the wall as your running guide, the blade drawn toward you in smooth pulls, one or two per wall run rather than a sawing dozen. The long point keeps your knuckles off the floor for the whole perimeter; that is the pass Hyde's "long-point blades protect from scraped knuckles" was written for. The 20550 takes the doubled thickness at a folded corner or a stiff commercial edge that would flex a lighter blade. Let the base or shoe molding cover the cut edge — the fit tolerance is whatever the base hides. Here glue-down forgives what stretch-in cannot: the subfloor under this cut is already covered in adhesive, so the open point's one real liability — gouging the substrate — matters least on this floor, which is part of why the pierce-and-pull knife is so at home in direct glue-down. The honest exception: where you trim at a doorway or transition onto a floor that continues — tile, wood, a metal transition strip — the substrate beyond *does* have to survive, and there the captured hook is the right answer: a 42200 hook blade in a utility knife, or the 67090 hook knife (both other lines), cut in a throat that physically cannot score what's beneath. And a carpet crew proper carries the carpet-specific hawkbills — 54020 / 54040 — and the replaceable-blade 42095 (carpet-knives line): the same pull-cut philosophy, sized and sold for the trade.

Cure on the label's clock. Keep foot traffic light and all rolling loads off until the adhesive cures to the manufacturer's number — a wet-set bond especially is not done the moment it feels grabbed. Hold furniture and heavy point loads off, and keep water off any seam until cure is complete. Felt pads under everything that returns to the floor.

Clean the tools before the adhesive decides for you. The trowel's notches are its entire value: wash the blade before the pail's residue kicks, on the label's cleaner — adhesive cured into a 1/16" meter, or a nick pried out of it later, under-delivers on every floor after this one. Wipe the knives' carbon blades clean and dry — carpet adhesive and a damp slab bloom rust on neglected carbon steel — and touch up the inside curve with a slip stone following the sweep (the full routine is *Sharpen and maintain a flooring knife*).

What goes wrong (and the fix)

Bubbles, or a lifted spot the day after. Swirled combing, skipped or late rolling, or carpet laid past the open time onto a skinned bed. Inside the window a bubble rolls out to the edge under the roller; after cure it is a slit-and-re-glue repair. Prevention is one-direction ridges (Step 7), rolling on time (Step 10), and reading the tack (Step 8).

You pulled a corner to check and there's no adhesive on the back. No transfer — the coverage failure, read exactly like a lifted tile back. Too-fine a notch for the backing, too-flat a blade angle, a bed that skinned before lay-in, or a thirsty slab that drank the adhesive without a primer. Full, even wet-out onto the backing is the target; bare backing means fix the notch, the angle, the timing, or the primer — in that order — before the carpet is down for good.

Adhesive bled up into the pile, or oozed at the seams. Over-notched meter, a too-wet bed laid too early, or seam edges jammed together. Clean it now with the label's cleaner — cured adhesive in the face yarn is permanent in practice — and next time lean the meter or let the bed flash longer.

A seam you can see — a gap or a peak. Edges that were never conjugate (the seam-guide rule skipped), no seam sealer so the edge raveled, or edges driven into a peak. Warm and still-open, re-press it flat; cured, it is trade repair work. Prevention lives entirely in the cutting and sealing, over in *Seam two pieces of carpet*.

The whole floor reads as two colors in raking light. Nap reversal — one piece laid against the pile direction of the rest. There is no cutting fix and no adhesive fix; it is prevented at layout with a nap arrow on every piece (Step 4). It is the placement doctrine's proof case, and it is the reason layout happens before adhesive and not after.

Load-bearing safety

Adhesive fumes — read the SDS, ventilate, and respect a flammable pail. Carpet adhesives run the range from water-based low-VOC latex to solvent-based systems, and some solvent carpet adhesives are labeled *extremely flammable* — spreading a whole room of one puts real vapor into a closed space. Ventilate the room while you spread and while the bed flashes, and on a solvent-based or flammable adhesive kill the ignition sources (pilot lights, sparks, smoking) for the same window. Prefer a low-emission adhesive where you can: the carpet industry's CRI Green Label Plus program tests adhesives for chemical emissions for exactly this reason (Building America Solution Center — certified low-emission carpet adhesives; reducing carpet-glue vapor exposure). The SDS in the box owns the specifics — read it before you open the pail, not after.

Asbestos, if an old floor is under this one. Inherited from the resilient trade and non-negotiable: pre-1980s resilient tile, sheet-goods felt, and black cutback adhesive can contain asbestos; you cannot identify it by eye, and a glue-down job's prep — scraping a slab clean — is disturbance. Test before you disturb; a positive result is an abatement decision, not a technique (EPA — Protect Your Family from Exposures to Asbestos). The full treatment is *Tear out old resilient flooring*.

The history footnote (because these pages should be worth reading)

Direct glue-down is the commercial answer to a residential invention. Glue-down took the other road entirely: bond the carpet flat to the slab and delete the pad, the strip, and the stretch. It is what let wall-to-wall carpet cover the postwar era's vast commercial concrete — offices, schools, corridors, basements — where a stretched floor over pad would ripple under rolling loads and a slab-on-grade gave a tack strip nothing to bite. The knife making the cuts is far older than either method: a sickle's inside-curve edge scaled to the fist, the same hawkbill the flooring-knives document dates to Frederick Walton's linoleum, renamed for each material that passed beneath it.

Tools this guide links back to: 19062 MAXXGRIP 1/16" square trowel (the workhorse carpet meter) · 19040 economy double-U trowel (lighter goods; four edges to rotate) · 20200 Flooring Knife (rough cuts, mid-field starts, wall trim) · 20550 Black & Silver Flooring/Roofing Knife (heavy backing, doubled edges, tear-out). Honest cross-line — this store's members lead, and these are the right answer only where a buyer's path genuinely crosses: 42200 hook blades / 67090 hook knife (captured-hook trimming at a transition onto a floor that must survive) · 54020 / 54040 / 42095 (carpet-specific knives) · [09086] knee pads. Cross-linked guides: *Seam two pieces of carpet* (the seam-edge cutting — this guide is its adhesive side) · *Rough-cut carpet from the back* · *Tear out old resilient flooring* (the asbestos boundary) · *Remove floor adhesive and mastic* · *Install sheet vinyl* · *Install linoleum* (resilient siblings) · *Match the notch to the covering and adhesive* · *Sharpen and maintain a flooring knife* · *Keep a carpet knife cutting*.