Wood Floors: Glue-Down vs Floating
What we’re comparing
For products that allow both methods (mostly engineered wood; sometimes laminate/LVT hybrids):
- Glue-Down: Boards bonded to the substrate with elastic wood adhesive.
- Floating (Underlay): Click/lock or tongue-and-groove boards laid over an acoustic/moisture underlay, not bonded to the slab.
Performance differences
Stability & feel underfoot
- Glue-Down: Firm, “solid” feel; less drum sound; better dimensional stability in larger rooms.
- Floating: Slight spring and more hollow sound unless you use premium underlay.
Acoustics (impact & airborne)
- Glue-Down: Typically quieter (lower impact noise transfer).
- Floating: Depends on underlay; good underlays can help, but still a touch louder.
Room size & transitions
- Glue-Down: Handles bigger continuous areas with fewer expansion breaks.
- Floating: Needs expansion joints at doorways/long runs per manufacturer limits.
Underfloor heating (UFH)
- Glue-Down: Best heat transfer and response (fewer layers).
- Floating: Slightly slower response; choose low-tog underlay and respect surface temp limits.
Moisture tolerance
- Glue-Down: With the right adhesive/DPM, copes well over concrete; no polyethylene trapped layer.
- Floating: Relies on underlay with integrated vapor barrier; edge sealing is critical.
Repairs & replacement
- Glue-Down: Board replacement is surgical (cut-out); harder but permanent.
- Floating: Panels can be lifted/backtracked (easier spot repairs), if access allows.
Height build-up
- Glue-Down: Lower profile (no foam layer) — useful at doors/stairs.
- Floating: Adds 2–4+ mm for underlay; may affect thresholds.
Finish longevity
- Glue-Down: Less deflection → finish edges and click joints suffer less over time.
- Floating: Micro-movement can stress click edges if subfloor isn’t very flat.
Subfloor & installation
Flatness tolerance
- Glue-Down: Wants very flat subfloors (often ≤2–3 mm over 2 m); may require more prep.
- Floating: Slightly more forgiving, but still needs good flatness to avoid bounce/lippage.
Programme speed
- Glue-Down: Slower per m² (adhesive trowelling, cure time).
- Floating: Faster install; rooms can return to service sooner.
Edge details
- Glue-Down: Skirtings can be tighter; less need for large trims.
- Floating: Mind expansion gaps; trims/profiles at thresholds are common.
Cost guide (percentages only; baseline = Floating with standard acoustic underlay = 0%)
(Comparable engineered wood product; site, adhesive brand, and prep can shift ranges.)
- Materials (adhesive/DPM vs underlay): Glue-Down +5–20% vs baseline
- Labour (install): Glue-Down +15–35% vs baseline
- Subfloor prep (screed/levelling): Glue-Down +0–15% vs baseline (tighter flatness)
- Lifecycle/maintenance over ~10–15 yrs: Glue-Down −5–15% vs baseline (fewer movement-related touch-ups)
- Programme/downtime: Glue-Down +10–25% vs baseline (adhesive cure; staging)
Advantages & benefits
Glue-Down
- Premium, solid feel and quieter footfall
- Better for UFH and large open plans
- Lower height build-up; fewer transition breaks
- Often longer-term stability (edges, squeaks)
Floating (Underlay)
- Faster and cleaner installation
- Easier repair/partial replacement
- Underlay can add acoustic or moisture benefits in one layer
- Ideal where you want minimal substrate intervention
Risks & how to avoid them
Glue-Down
- Bond failure if slab moisture is high → use moisture testing (RH/CM) + epoxy/PU DPM where required.
- Telegraphing from imperfect subfloors → self-level to spec; use manufacturer’s trowel notch and open time.
Floating
- Creaks/bounce from uneven subfloors → flatten first; use dense underlay.
- Moisture trapping with wrong underlay → choose vapor-barrier underlay on concrete; tape seams.
- Click damage during install → gentle tapping blocks; maintain expansion gaps.
Quick choice guide
- UFH, large open rooms, premium feel, minimal thresholds? → Glue-Down
- Speed, easier future access/repairs, rental turnovers, budget-sensitive? → Floating (Underlay)
Pro tips
- Check manufacturer approval: some floors are rated for one method only or require specific adhesives/underlays.
- Keep surface temperature ≤27–29 °C for wood on UFH; stage heat-up after installation.
- Protect finished floors during the rest of the works (boards/card + film) to avoid early damage, especially with floating systems.
