The most common reason a brand new carpet fails within two or three years is not the carpet. It's not the underlay. It's the subfloor beneath both — specifically, a subfloor that wasn't properly assessed or prepared before the first tile of carpet was laid.
Most carpet fitters in Peterborough don't tell customers this because subfloor preparation adds time and cost to a job. We tell customers this because a poorly prepared subfloor wastes every pound they've spent on carpet and underlay, and because we won't fit on a subfloor we're not satisfied with. This guide covers what subfloor preparation actually involves, what it costs, and what questions to ask any fitter before they start work.
For a free home survey and honest subfloor assessment anywhere across Peterborough PE1–PE7, call 07345 995206 or email contact@cambridgeshirecarpets.co.uk.
Why Subfloor Preparation Matters More Than Most People Think
A carpet laid on a poor subfloor is a guaranteed problem. The specific failure mode depends on what's wrong with the subfloor:
An uneven subfloor (lumps, dips, protruding nail heads, board edges) transmits every imperfection through the underlay and carpet. You'll feel the bumps underfoot, they'll accelerate localised wear on the carpet pile directly above them, and within a few years the carpet will show obvious wear patterns over the problem areas.
A damp subfloor causes underlay to break down, carpet backing to delaminate, and in timber floor applications can cause the boards to move or swell, lifting the carpet. In serious cases, mould grows beneath the carpet invisibly — a health risk that becomes apparent only when the carpet is eventually lifted.
A dirty subfloor — old adhesive residue, grit, staples, loose material — prevents underlay from lying flat and creates points of localised pressure on the carpet above.
Types of Subfloor in Peterborough Properties
Peterborough's housing stock spans multiple eras with different subfloor constructions. Understanding what's likely beneath your carpet is the first step.
Victorian and Edwardian Properties (PE1 City Centre, Parts of PE2)
Older properties in Peterborough's city centre and inner suburbs typically have suspended timber floors — floorboards over floor joists with a void beneath. These properties require:
- Board re-pinning or re-screwing where boards are loose or springy — a loose board will creak and eventually cause the carpet to ridge along the board edge
- Hardboard overlay in most cases — the narrow-width floorboards in older properties are too irregular to lay carpet directly without telegraphing the board joints through the underlay. A 4mm hardboard or plywood overlay laid diagonally smooths the surface and provides a uniform fixing base for gripper rod
- Inspection of the void for damp: older properties with poor subfloor ventilation can trap moisture beneath the boards, which migrates up into the underlay. We assess this on survey
1930s–1970s Properties (Walton, Dogsthorpe, New England, Orton Goldhay)
Mid-century housing across Peterborough's established suburbs often has solid concrete subfloors with screed — either the original concrete with a levelling screed, or screeded concrete with old adhesive residue from previous vinyl or tile installations. Key preparation requirements:
- Old adhesive removal: previous vinyl, cork or ceramic tile adhesive must be removed or stabilised before carpet underlay is laid. Bitumen-based adhesive (common in 1960s–1970s properties) requires specialist treatment and may test positive for asbestos content if the original tiles remain — these must be tested before removal
- Screeded concrete moisture testing: even solid ground-floor concrete can have rising damp, particularly in properties without a cavity wall DPM. We test with a calibrated hygrometer — anything above 75% RH requires a damp proof membrane before fitting
- Levelling: older screed surfaces are rarely flat to the 3mm/1.8m tolerance required for a quality carpet installation. Self-levelling compound is often needed
New Build Properties (Hampton PE7, Cardea, Great Haddon, Fletton Quays)
New build concrete subfloors present a specific problem: construction moisture. A newly poured concrete slab contains significant residual moisture that takes 12–24 months to fully dissipate under normal conditions. Many new build developers and buyers are unaware that fitting carpet — or any floor covering — too early traps this moisture, causing underlay breakdown and carpet backing delamination.
We test all new build subfloors before committing to a fitting date. If moisture levels are high, we advise waiting — not fitting regardless and hoping for the best. See our dedicated guide on carpets for new build homes in Peterborough for the full picture on new build subfloor management.
What Subfloor Preparation Costs in Peterborough (2026)
These are realistic preparation cost ranges based on typical properties across the PE postcode area. Costs vary significantly depending on the property, the existing condition, and the products required:
- Board re-pinning/re-screwing: £0.50–£1.50/m² depending on extent of loose boards
- Hardboard overlay (4mm, for timber floors): £3–£6/m² supply and fit
- Plywood overlay (6–9mm, for uneven or bouncy timber floors): £6–£12/m² supply and fit
- Old adhesive removal (light residue, mechanical): £4–£8/m²
- Old adhesive removal (heavy bitumen, specialist treatment): £8–£18/m²
- Asbestos tile testing: £100–£200 per visit (essential before disturbing any pre-1985 tiles)
- Self-levelling compound (standard depth, concrete floors): £8–£18/m²
- DPM (liquid damp proof membrane, concrete floors): £5–£10/m²
- Moisture testing (calibrated hygrometer reading): Included in our survey at no additional charge
The Preparation Questions to Ask Any Carpet Fitter
Before accepting any carpet fitting quote in Peterborough, ask these questions. How the fitter answers them tells you everything about whether they'll do the job properly.
- "Will you test the subfloor for moisture before fitting?" — A professional fitter should confirm they will test, not just look. Visual inspection does not detect subsurface moisture. Any fitter who says "it looks fine" without testing is not protecting you.
- "What will you do if the subfloor isn't flat enough?" — The acceptable answer is "we'll level it with self-levelling compound" or "we'll overlay with hardboard." An answer of "it'll be fine" is not acceptable for a quality installation.
- "Are old tiles or adhesive present on the floor?" — If so, ask whether they'll test for asbestos before disturbing. Pre-1985 floor tiles may contain asbestos. This is not optional.
- "Is subfloor preparation included in the quote, or quoted separately?" — Be wary of quotes that don't address preparation at all. The real cost becomes clear on fitting day — after your carpet has been delivered.
At Cambridgeshire Carpets, our survey process covers all of these questions before we issue any written quotation. We don't confirm a price until we've seen the subfloor condition — because we won't quote for a job we can't guarantee. See our how we work page for the full survey process.
Preparing Your Floor Before the Fitter Arrives
If you've booked a carpet survey or fitting, here's what you can do to prepare the room:
- Remove all furniture — or confirm with the fitter whether they will move it. Many fitters charge additionally for furniture removal
- Remove any loose rugs, mats or existing carpet if you've arranged fitting-only (we remove the old carpet on supply-and-fit jobs)
- In new build properties, leave heating running at normal room temperature for at least 4 weeks before the fitting date to help moisture dissipation
- If you have pets, arrange for them to be out of the house on fitting day — both for the fitter's comfort and to prevent pet hair being trapped beneath the carpet during installation
Call 07345 995206 for a free home survey anywhere across Peterborough and Cambridgeshire. Our survey covers subfloor assessment, room measurement, and product recommendation — at no charge and no obligation. Read our complete carpet buyer's guide for Peterborough for the wider context on carpet selection and fitting.
Frequently Asked Questions — Subfloor Preparation for Carpets in Peterborough
How do I know if my subfloor needs preparation?
Visual signs include: boards that creak or move when walked on, visible ridges or dips in the existing floor, old adhesive or tile residue on concrete floors, or damp patches visible on the floor or walls near floor level. However, the most reliable assessment comes from a professional survey — particularly for moisture, which is invisible to the naked eye but detected quickly with a calibrated probe. We survey all floors before fitting at no charge.
Does old carpet need to be removed before fitting a new one?
Always. Fitting new carpet on top of old carpet is never appropriate — the combined depth affects door clearances, creates an unstable base, and traps any contamination in the old carpet beneath the new one. We include removal of the old carpet as standard on supply-and-fit jobs. On fitting-only jobs, the customer is responsible for removing the old carpet before our fitters arrive.
How long does subfloor preparation add to a fitting job?
Standard board re-pinning on an average room adds 30–60 minutes. A full hardboard overlay adds 1–2 hours per room. Self-levelling compound application adds 24 hours of drying time before the carpet can be laid — this is factored into our project schedule. If significant preparation is needed across multiple rooms, we schedule a preparation day before the carpet fitting day, so nothing is rushed.
My new build developer says the floor is ready — is it?
Not necessarily. Developers work to handover schedules, not to flooring-readiness standards. A newly completed concrete slab in a Hampton PE7 new build may test at moisture levels far above the 75% RH threshold safe for carpet installation, even if the developer says the property is "ready to occupy." We test independently and advise based on the actual reading — not the developer's schedule.
Can I carpet over underfloor heating?
Yes, but specification matters. Carpet tog rating must be checked — the combined tog of carpet and underlay must stay within the heating system manufacturer's specification (typically below 2.5 tog total). Some premium underlays are designed specifically for underfloor heating and provide a stable base while maintaining thermal conductivity. We supply underfloor-heating-compatible underlays and will specify appropriately for your system. Call 07345 995206 to discuss your requirements.