Loft insulation in Cranborne

Work on a Cranborne loft tends to follow a cold upstairs, a thin layer or condensation. A cold upstairs that the boiler never quite gets ahead of. A loft somebody has finally looked into and found thin, flattened or bare at the edges. Or condensation showing up on the underside of the felt, with black mould starting on the rafters.

Whichever of those it is, we come out to Cranborne and look before there is any talk of depth. What is up there, how deep it truly is, where the joists run, whether the eaves are open, and what has been stored on top of it. The site visit is free and so is the itemised written quote. If the ceiling is already fine, we would rather tell you that than sell you rolls.

Taking stock of what is there. Very few lofts in Cranborne are empty, and very few are right. The usual picture is an old layer that has settled to two thirds of what it started at, compressed hard wherever anyone has walked, patchy where a cable or an aerial went in, and stopping well short of the wall.

Anything contaminated with droppings, or damp from a slipped tile, comes out in bags and leaves with us. Sound material stays put and gets built on.

The depth, and why the second layer runs the other way. Finished depth in a Cranborne loft is about 270mm. The first layer of mineral wool roll sits between the joists, friction fitted so there is no gap at the edge, and the second is cross laid over the joists so the timber itself is covered. Leave the joists proud and every one of them becomes a cold bridge, which is why a loft that looks tidy from the hatch can still be losing heat in stripes. Glass wool roll suits most bays, rockwool batts suit a cut roof with odd spacings, and loose fill goes where a roll will not lie flat. Approved Document L sets the U value the finished ceiling should reach.

Air, before insulation. Insulating a ceiling makes the roof above it colder, which moves the dew point up into the structure. Warm vapour drifting out of the house then meets cold felt, and you get droplets, damp insulation and mould on the timbers. So the eaves stay clear. Insulation stops on the wall plate, vent trays hold it back so there is an unbroken air gap, and cross ventilation moves air from one eaves to the other. On a roof where the eaves are closed up, ridge vents or vent tiles take over. Approved Document F is the standard behind it.

What else lives up there. Downlighters get rated covers so they are not smothered. Cables are pulled clear of the wool and clipped to the joists. In older houses there is usually a cold water tank and a run of pipework that has just been moved to the cold side of the building, so lagging and a tank jacket go on the same visit. The hatch gets insulated on its back and draught sealed, because a bare trap is a hole in a good ceiling.

Storage, and the parts with no loft at all. Where you need the space, a raised floor on loft legs keeps the boarding clear of the full depth instead of crushing it. Plenty of older houses in Cranborne have rooms tucked into the roof, so there is no flat loft to roll out: that is rafter level work, rigid PIR board cut between the rafters with a clear gap under the underlay, a layer beneath, taped joints, and a warm roof build up that keeps interstitial condensation out of the timber.

Thomas goes up into the loft himself, checks how deep and how sound the old insulation is, looks at the air flow at the eaves and for any sign of damp, and prices it there. Emptying the loft and insulating it come under the one quote.

The quote lists the survey, bagging and removing what is up there, the new material and its depth, trays to keep the eaves clear, the hatch, any pipework, and disposal.

In an older Cranborne cottage the hatch can be small and over the stairs, and the roof space low and awkward. A converted barn may have no loft floor at all. We lay mineral wool or a natural fibre between the joists and a second layer across them, keep the eaves open, lag the pipes and tank, and insulate and draughtproof the hatch. Dust sheets run from hatch to front door, and old material is bagged in the loft and carried out. A leak, woodworm or a damp patch found up there is photographed and costed for you before anything else.

Insulating a roof space is not development and leaves permitted development rights alone, as Planning Portal guidance on insulation confirms. Building control applies when more than half of a thermal element such as the roof is renovated, under regulation 23. Being in a conservation area makes no difference to loft work, but on a listed building listed building consent can cover work inside too. Check the VAT treatment of energy saving materials before you order.

The first check is to look up into the Cranborne loft with a torch. If the felt is beaded with water, black mould is creeping along the rafters, or the insulation feels damp in your hand, moist air from the rooms below is condensing in a loft with too little ventilation.

Left to carry on, it rots timber. Do not add insulation yet. See whether old insulation has been pushed into the eaves and blocked them, and whether the bathroom fan is ducted outside or just blowing into the roof. On the first visit Thomas tells condensation from a leak and works out what needs to change before anything more goes in. Loft jobs are booked Monday to Friday, 8am to 6pm. If the loft is wet, telephone rather than use the form, and if nobody is free to answer, we ring back as soon as possible.

Call now: 07435 839745

A lot of Cranborne is not on the gas main. Heat comes out of an oil tank in the garden, or off bottled gas, or straight off the meter. That does not change one thing about how we lay insulation.

It changes what the same insulation is worth to you, because the fabric decides how much heat you have to buy and the fuel decides what that heat costs. The same loft, done to the same depth, saves more in an oil heated house than in one on mains gas.

It also changes the order in which we would spend your money. On oil the demand shows up as a delivery rather than a monthly bill, so it is easy to miss how much of it goes through the ceiling. Ceiling depth and draught sealing come first, because they cut what the boiler has to make. Then the sloping ceilings and the room in roof, which in an older house are often losing more than the flat loft ever did. Then everything else. If somebody has quoted you for a new boiler and nobody has been up into the roof, get the roof looked at first.

Nearby places we also cover for loft insulation, with straight-line distances from Cranborne, and the other trades we offer in Cranborne itself.

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