Flooring Fitters in Chellaston

Chellaston is one of the parts of Derby that has grown fastest, and the housing reflects it. An old village core around the church and High Street, a substantial band of postwar development around that, and then estate after estate of modern building filling the ground out towards Boulton Moor and the A50.

That last group is the biggest share of what we are asked to do here, and it comes with a technical question that almost nobody gets told about until it goes wrong. It is about what the floor is made of before you ever choose a covering.

Chellaston sat on one of the best beds of gypsum in the country, and the pale alabaster quarried here was carved into tomb effigies and church monuments from the Middle Ages onwards. It travelled a long way — Chellaston stone ended up in cathedrals and parish churches across England and was exported to the continent.

That is a piece of local history rather than a flooring fact, but it earns its place on this page for an odd reason. Gypsum is what modern liquid screeds are mostly made of, and a very large number of the newer houses in Chellaston have one under the floor. Which brings us to the thing worth knowing.

Modern houses with wet underfloor heating are usually built on a liquid screed poured over the pipes. Most of those screeds are calcium sulphate based — anhydrite, in other words gypsum — rather than the sand-and-cement screed people picture. They are excellent for the purpose. They also behave completely differently from cement, and three things follow.

First, they dry slowly. A rough working figure is around a millimetre a day for the first 40mm and slower after that, which means a 50mm screed can be looking at two months in good conditions and considerably longer in a cold, unheated house over winter. Moisture has to be measured rather than assumed, and the heating has to be commissioned and run through a proper warm-up cycle before a floor goes down.

Second, laitance has to come off. A weak, dusty skin forms on the surface as the screed cures. Anything laid onto it is bonded to that skin rather than to the screed, and it will eventually let go. It is removed by sanding, and it is the step most often skipped because it makes mess and takes a day.

Third, and the one that causes genuine failures: gypsum and cement do not get on. Use an ordinary cement-based levelling compound or a cement-based tile adhesive straight onto a calcium sulphate screed and the two react in the presence of moisture, forming ettringite, which expands. The bond fails. The floor lifts. The correct route is a suitable primer and a compatible compound or adhesive, chosen for a calcium sulphate base.

None of this is exotic and none of it is expensive. It is simply a different sequence from the one most people assume, and it is why we ask what the subfloor is before quoting a new-build floor rather than after.

Where there is heating in the floor, the covering has to let the heat through. The measure is tog, and the combined figure for the covering and anything beneath it generally needs to sit at or below about 2.5 tog. Your heating manufacturer will state its own maximum and that figure takes precedence over any rule of thumb.

In practice LVT, sheet vinyl and tile all work well over heating because they are thin and conduct readily. Laminate and engineered wood work with the right underlay and the right board thickness. Carpet is possible but only with a low-tog underlay made for the job, and a thick felt underlay will undo the whole system.

Solid wood over underfloor heating is the one we usually talk people out of. It moves too much with the heating cycle. Engineered board does the same job and stays where it is put.

If the house is still being built or the extension is at planning stage, the conversation is much easier before the screed is poured than after. More on underfloor heating if that is where you are.

Not all of Chellaston is new. The older core and the postwar streets around it have conventional floors — solid concrete downstairs, timber upstairs — and none of the screed questions above apply.

What does apply there is the usual pattern for houses of that age. Settled solid floors that are no longer flat and want a levelling coat before anything is laid, and first-time whole-house jobs after twenty or thirty years of the same carpet.

Access is generally easy in this part of Derby — driveways, wide roads, somewhere to put a van — which keeps fitting days shorter than they are in the older terraced parts of the city, and that shows in the price.

The shops and units along the High Street and the newer local centres carry the usual suburban mix: salons, takeaways, a pharmacy, small offices and a fair number of home-based businesses that have outgrown the house.

Food premises want welded safety vinyl with coved skirtings. Salons want something that shrugs off tint and bleach. Offices and consulting rooms are usually carpet tiles, lifted and swapped one at a time rather than recarpeted.

Work is scheduled around your closed day or after hours. Tell us the window when you ask for a price.