Substrate, DPM, insulation, edge insulation and UFH set-out, the unsexy work that decides whether your liquid screed performs for 50 years or fails inside 50 days.
Floor preparation is everything that happens between the structural deck (slab, beam-and-block, suspended timber) and the screed pour. DPM, insulation, edge insulation, taped joints, UFH pipework, levelling correction, all the layers that decide whether the finished floor performs.
Anyone pouring liquid screed who doesn't have an in-house prep crew. Housebuilders running multiple plots, commercial main contractors managing trades, self-builders who'd rather hand off the prep, and refurbishment projects where substrate condition is unknown until you lift the old floor.
Always. Liquid screed is only as good as the prep beneath it. The fastest way to fail a pour is to skimp on prep, and the cheapest way to add years to a floor's life is to get the prep right first time.
Floor prep is where most floor failures originate, not in the screed itself, not in the floor finish, but in the layers between. Bad DPM laps, untaped insulation joints, missing edge insulation, and unrestrained UFH pipework cause cracking, curling, hot-spots, and failed moisture tests months after the building looked finished.
We've been called to enough failed-screed jobs to know exactly where it goes wrong. It's almost never the screed.
Missing or punctured DPM means moisture rising into the screed, into the floor finish, and into the homeowner's complaint inbox. Rectification means lifting the floor, the screed, and starting again.
Liquid screed expands and contracts. Without edge insulation around the perimeter and around every column, restraint cracks open up exactly where the floor finish is hardest to repair.
Pipework lifting during the pour, unrestrained pipe loops, or insufficient cover above the pipe all kill the heating performance the homeowner paid for.
Trodden-on, torn, water-damaged insulation underperforms by 30–50%. We supply and lay fresh insulation as part of the prep package.
Untaped insulation joints leak slurry, leak warmth, and create acoustic bridges. Taping is fast, cheap, and non-negotiable.
Datum levels, cleanliness, hollows, high points, we check every site before the first material is delivered.
Call us with postcode, area and timing. We give you an indicative price on the spot, often within minutes.
For local jobs we visit, measure, and confirm specification for your floor preparation at no charge. Charges may apply for surveys further afield, agreed up front.
Written quotation in your inbox within one working day of the survey, confirming m² rate, mix design and a firm pour date. All quotes subject to site survey.
Our crew arrives on time with kit, pumps and labour. Continuous flow, level checks, and a clean handover at the end of shift.
Moisture testing on request and after-care guidance so the next trade can start with confidence.
Right prep means the screed and the floor finish on top of it last as long as they should.
Properly laid DPM and edge insulation means the screed dries on schedule and the floor finish installer can start on time.
Correct insulation depth and pipe restraint means every watt the boiler produces ends up in the room, not the foundation.
Prep and pour from the same crew means no finger-pointing if anything ever goes wrong. We own it end-to-end.
We schedule prep, pour and dappling as one job, no waiting for separate contractors to find a slot.
We follow the architect's spec, the engineer's loading, the UFH designer's pipe layout. Everything traceable, everything documented.
Floor preparation is layer-by-layer detail work. Here's what we install and why each layer matters.
Every prep starts with assessing what's underneath. New-build slab: check levels, datum, surface contamination. Beam-and-block: check infill condition, level variance. Refurbishment: lift sample area, check existing floor build-up, check for asbestos, check for damp. We do this before any material is ordered.
Polythene DPM (1000g or 1200g) laid in continuous sheets with 150mm taped laps and turn-up at perimeter. Penetrations (pipes, columns) detailed and taped. For damp substrates or particularly aggressive moisture conditions we specify liquid-applied DPM. Done once, done right, never visible again, but the entire floor depends on it.
PIR boards (Celotex, Kingspan, Recticel) at 100–150mm typical for new-build floors. EPS for budget projects. XPS for high-load commercial. Cuts butted tight, joints taped, perimeter edge insulation 8–10mm to allow screed movement. We supply and lay all of it as part of the prep package.
We work to the UFH designer's layout, typical 150–200mm pipe centres for domestic, varied for room loads. Pipework clipped to the insulation at correct intervals, restrained at penetrations, and pressure-tested to the manufacturer's spec before pour. We hold pressure during the pour so any leak shows immediately, not under a finished floor.
8–10mm flexible edge insulation around every perimeter wall, every column, every doorway threshold. Movement joints designed into large pours and at changes of geometry. This is the detail that prevents cracking and curling, and the detail most often skipped on price-driven prep quotes.
Real photos from recent South Wales floor preparation jobs, pump set-ups, pour days and finished floors.
Typically £8–£15 per m² for full prep package including DPM, insulation, edge insulation and pipe clipping, depending on insulation depth and complexity. Quoted with the screed pour as one combined price.
Yes, full material supply included in our prep package. We use Celotex/Kingspan PIR as standard with 1200g DPM. Specific products can be specified to architect's preference.
Yes, strip-out and skip removal can be quoted as part of the project. We assess condition and disposal route on the site survey.
We can fix and pressure-test the pipework as part of the prep package, working to your UFH designer's layout. Or we can prep up to insulation and let your UFH installer lay pipework, then return for the pour.
Domestic plots typically 1–2 days for full prep. Commercial sites scale with area, typically 100–200m² per crew per day for full prep including pipework.
Minor variation is corrected with insulation packers or a thin levelling layer. Major variation may need a sand-and-cement infill or a thicker structural screed beneath the liquid screed, we'll specify on the survey.
Yes, full prep and pour service across South Wales and into Hereford from our Blackwood yard.
Not on day one. You'll see it in three years when the floor cracks, the heating doesn't work, or the floor finish lifts. Prep is invisible insurance against expensive future failure.
Tell us the postcode and the m². We give an indicative price on the call and firm it up in writing after a site survey.
From Blackwood, we pour daily in:
