Loft condensation investigation

What is a loft condensation investigation?

We inspect the loft in daylight and by torch, measure moisture in the timbers, check the underlay, ventilation, insulation and the routes that let warm air in from the house, and look at the roof from outside. You get written findings with photos and a plain list of what we recommend, which may include work we do not offer.

Is it right for your loft?

Water dripping from the felt in cold weather
Black mould on rafters or the back of the hatch
Wet patches on the insulation
Problems that started after new insulation was fitted

How we do it

We ask about the house: heating, drying washing, extractors and when it happens.
We inspect and measure in the loft.
We check the roof covering from the ground and the eaves.
You get a written summary and options.

What is included

Loft inspection with moisture readings
Check of insulation, ventilation and air leaks
Written findings with photos

Worth knowing

Condensation in winter is common and often harmless if it dries out. Persistent wetting that rots timber is not. If the cause is a roof defect, you will need a roofer, and we will tell you so.

How much does a loft condensation investigation cost?

£145 to £245Investigation visit with written findings. Priced before you book, with written findings afterwards.

This work is not an energy-saving material for VAT, so it is standard-rated if VAT applies. Where it is done alongside insulation, the quote shows each part separately.

Work out a guide price for your loft or see every price.

Do the rules differ across the UK?

Yes, a little. Building regulations and funding schemes are set separately in each nation. Here is the short version; each area page has the detail.

Nation	Building rules	Funding to check
England	Approved Document L; insulation alone is not usually notified	ECO4 to 31 Dec 2026; Warm Homes Plan and Warm Homes: Local Grant
Wales	Welsh Approved Document L; conversions need building control	Warm Homes Nest; ECO4 to 31 Dec 2026
Scotland	No building warrant normally needed; standards still apply	Home Energy Scotland grant and loan; Warmer Homes Scotland
Northern Ireland	NI Building Regulations (Technical Booklet F1); check with council building control	Affordable Warmth Scheme; NISEP

Questions about a loft condensation investigation

Is condensation in my loft normal?

A little on the coldest nights can be normal, especially with old felt. Dripping, wet insulation or mould are signs to investigate.

Can loft insulation cause condensation?

It can expose an existing problem: the loft gets colder, so the same moist air condenses more readily. Ventilation and sealing air leaks put it right.

Is the investigation fee taken off the work?

The investigation is priced on its own so the advice is not tied to selling work. You decide what to do afterwards.

Where we provide a loft condensation investigation

Wales

Scotland

Northern Ireland

Often booked with it

Why is there condensation in my loft after insulation?

Sources, checked October 2026: Energy Saving Trust: roof and loft insulation; Which?: loft insulation costs and savings; LABC: building regulation requirements for loft insulation; GOV.UK: extending the ECO4 end date, government response.