Acclimation

Acclimate boxes flat in the installation room for 48 hours at 65–85°F and 35–65% relative humidity before installing.

Pro tip: If boxes have been stored in a cold truck or warehouse below 50°F, let them sit in the install room for 24 hours before cutting. Rigid-core planks handle temperature change better than wood, but extreme cold can make the click-lock edges brittle during installation.

Subfloor flatness

Subfloor must be flat to within 3/16 inch over 10 feet. Fill low spots and grind high points before installation.

Pro tip: On older concrete slabs, we measure flatness in multiple directions — not just one straight line. A 3/16-inch dip in a 2-foot circle under a refrigerator telegraphs through even the thickest SPC eventually, regardless of what the 10-foot average says.

Moisture testing (concrete)

Test concrete subfloors per ASTM F1869 (≤ 5 lbs/1000 sqft/24hr CaCl) or ASTM F2170 (≤ 80% RH).

Pro tip: Bay Area homes near the water (Alviso, parts of San Mateo, coastal San Francisco) often have higher slab moisture than the test-day reading suggests — slab moisture fluctuates seasonally. If your slab tests at 85% RH in October, it may hit 95% in February. Budget for the 6-mil moisture barrier below either way.

Moisture barrier (concrete subfloors)

A 6-mil polyethylene moisture barrier is required over concrete subfloors. Not required over wood subfloors that pass moisture testing.

Pro tip: We recommend 6-mil polyethylene vapor barrier over every concrete subfloor regardless of test results. Seasonal moisture shifts, future plumbing leaks, and unseen slab cracks mean a clean moisture test today doesn’t guarantee a dry subfloor in five years. 6-mil poly is $30-50 for a whole room — inexpensive protection. Overlap seams by 6-8 inches, seal with waterproof tape, run 2-4 inches up the walls (hidden by baseboard). This is industry-standard per NWFA and what we’d do in our own home.

Underlayment (do not replace the attached pad)

No additional underlayment required — 1.5mm IXPE anti-microbial acoustic pad is factory-attached.

Pro tip: Customers sometimes ask about adding a thicker pad under Marseille Collection for more softness. Don’t. The attached anti-microbial acoustic IXPE pad is engineered to work with the SPC core — adding a second pad creates an unstable stack-up that causes click-lock seam failure over time. The warranty specifically voids structural-integrity coverage if a non-manufacturer pad is used.

Installation method

Floating click installation. Leave 1/4-inch expansion gap at all walls and fixed objects. Do not glue or nail.

Pro tip: For rooms wider than 25 feet or longer than 40 feet continuous, add a T-molding expansion break. SPC is dimensionally stable but not dimensionally inert — large rooms need room to breathe. Ignore this on thicker SPC at your peril; the extra thickness makes seam pressure more pronounced when expansion has nowhere to go.

Radiant heat compatibility

Radiant heat compatible. Maximum surface temperature 80°F. Heat must rise gradually (no more than 5°F per hour during initial warm-up).

Pro tip: Manufacturer spec: Radiant heat compatible. Maximum surface temperature 80°F. Heat must rise gradually (no more than 5°F per hour during initial warm-up). Turn the heating system on at least two weeks before installation to purge slab moisture. After installation, raise temperature in 5°F increments per day back to operating level. Never go from room-temp to full heat in one day — thermal shock can compromise the click-lock edges and anti-microbial acoustic IXPE pad adhesion.

Daily maintenance

Sweep or dry-mop regularly. Clean with a damp mop and pH-neutral cleaner. Never use wax, polish, steam mops, or abrasive cleaners.

Pro tip: Use a cleaner specifically labeled for luxury vinyl or SPC — Bona Pro Series Luxury Vinyl Floor Cleaner works well. Avoid ‘mop and shine’ products that leave a film; they trap dirt and dull the Ceramic Bead finish over time.

What to avoid

Avoid prolonged direct sunlight without UV-protective window film. Do not use rolling chairs without protective floor mats.

Pro tip: Steam mops are the #1 warranty-void cause on Medieval Floors floors — Medieval Floors’s master warranty explicitly denies coverage for any damage caused by steam cleaners, and the moisture/heat breaks down the adhesives in the plank construction. Customers sometimes say ‘but it’s waterproof’ — the core is waterproof; the seams and adhesives are not designed for pressurized hot water.

Furniture and pet protection

Use felt pads under all furniture legs. For heavy items, use wide-base coasters to distribute weight.

Pro tip: Office chairs with plastic wheels are harder on SPC than pet claws. Medieval Floors’s warranty specifically excludes damage from caster wheels unless they’re wide rubber — swap plastic wheels for rubber or silicone, or use a chair mat. This is in the written warranty, not a suggestion.