Roof Insulation & Ventilation Assessment in Dorset
Correct ventilation prevents condensation and damp from spreading through the roof structure — we inspect, test, and advise before recommending any work.
Why Ventilation Matters
A common issue we see in existing pitched roofs is a lack of correct ventilation, leading to condensation build-up. If a roof area can't 'breathe' efficiently, damp builds up and gradually spreads across the roof and timber structure. We inspect roofs from both inside and outside to determine whether ventilation is correct, and what the options are if it isn't.
One issue we consistently come across is the breather membrane itself. Older felt breathers allow minimal ventilation, and the laps shrink over time, creating gaps in the system. Once condensation starts to form, moisture finds its way behind the membrane and into the roof space — and this can go unnoticed until the timber has already started to take damage. Catching it early is almost always cheaper and less disruptive than waiting for visible signs like staining, sagging felt, or a musty smell in the loft.
There's a range of products designed to improve ventilation on pitched roofs, and which one suits a property depends on its construction. Options include vented slates and tiles, vented dry-fix ridge systems, mushroom vent pipes, and over-fascia vents. Where more detail on the existing roof build-up is needed, we can also arrange a core sample test — a small section taken with a core drill down to the joists, fire-safety tested and patched over, giving us an accurate read on moisture levels within the existing materials.
Ventilation Assessed Properly, Not Guessed
Roofs inspected from inside and outside to assess ventilation and damp
Breather membrane condition checked — a common source of hidden condensation issues
Vented slates/tiles, dry-fix ridge systems, mushroom vents, and over-fascia vents all considered against your roof's construction
Insulation and U-value advice — most pitched roofs are a 'cold roof' with only the ceiling insulated, and adding insulation to the pitch (with correct ventilation) improves energy efficiency
Core sample testing available where more detail on the existing build-up is needed
Site visits available so our team can talk through the analysis and proposal in person
How We Assess Ventilation Issues
Initial Inspection
We inspect the roof from inside and outside, checking the breather membrane, existing ventilation provision, and any visible signs of damp or condensation.
Core Sample Testing (Where Needed)
If more detail is needed, we take a small core sample down to the joists to check the existing build-up and moisture levels. The section is fire-safety tested and patched over.
Report & Recommendations
You receive a full written report covering our findings, along with a breakdown of ventilation options — vented tiles, dry-fix ridge systems, mushroom vents, or over-fascia vents — and costs for each.
Installation & Sign-off
If remedial work is agreed, we carry it out to the specification confirmed in the report, then walk you through the completed work and hand over any relevant documentation.
More Ways We Can Help
From surveys to finishing touches, we cover every part of the job.
Roof windows supplied, fitted, and sealed, integrated into the roof system with the correct flashing kit.
Dormers, flashings, valleys, and lead slate/tile detailing, repaired or renewed.
uPVC fixtures replaced or restored, resolving blockages and standing water.
Full roof assessment from above where access is difficult or unsafe.
What Our Customers Say
★★★★★“Really impressed with Lee and Sam and their team, from quotation to completion, the guys were courteous, punctual, tidy and professional. Their level of communication, planning and finish is exemplary. We couldn't recommend them enough. Quality professionals, providing a first class workmanship on the agreed price. If you need work done look no further.”
★★★★★“We needed our whole pitched roof completely refurbished and the insulation upgraded. Sam & Lee were very helpful from the initial consultation, backing this up with a very detailed step by step proposal. The work was carried out on time and very efficiently. The site was left tidy every day and we were kept up to date with the progress at the end of each day. Highly recommend to anybody looking for a local roofing expert with very competitive pricing. Very friendly team.”
★★★★★“We had a new double storey extension built at our house and contacted the Pitched Roofing Company to provide a quotation for the new roof. The guys came round the following day to discuss and run through the options and ideas. Each stage of the process they were very informative and professional. The work was carried out to the highest standard and they really put our mind at rest as it was a big decision for us to complete this work.”
★★★★★“Very polite gentleman, always a smile and very reliable. I can see the roof from the upstairs of the house and I am very satisfied with the work completed. Quoted a better price than 2 others in the local area and Sam was very helpful with explaining the process.”
★★★★★“Fantastic guys who are very friendly and very professional. So pleased we got the roof done properly and with such a high performance material. Going to use them again to build a green roof on the summerhouse!”
We'll assess it properly before recommending anything, so you know exactly what's needed and why.
Get a Free AssessmentRoof Ventilation Assessments Across Dorset & Hampshire
Working from Poole puts Bournemouth, Poole, and Christchurch on our doorstep, and we regularly carry out ventilation assessments across the wider Dorset area, into the New Forest and Ringwood, and through to Southampton and Hampshire for larger or phased projects. Condensation and ventilation issues are easy to miss until damage has already started, so being able to attend a survey quickly — and return promptly if remedial work is needed — makes a real difference.
The usual signs are condensation on the underside of the roof, damp or staining on roof timbers, a musty smell in the loft, or sagging felt between the rafters. None of them are conclusive on their own, which is why we inspect from inside and outside before saying what the cause is.
Warm, moist air rising into a roof space that cannot breathe efficiently. Older felt breather membranes are a frequent culprit — they allow minimal ventilation and their laps shrink over time, leaving gaps where moisture gets behind the membrane and into the roof structure.
We take a small section with a core drill, down to the joists, to check the existing build-up and moisture levels. The section is fire-safety tested and patched over afterwards, so the roof is left watertight.
Most pitched roofs are a cold roof: insulation sits at ceiling level and the roof space above it is unheated. Insulating the pitch itself brings the roof space inside the thermal envelope, which improves energy efficiency — but only works properly when ventilation is designed alongside it.
For a typical house, an hour or two on site covers the internal and external inspection. A core sample, where one is needed, adds a little to that. The written report follows afterwards.
We need access to the loft or roof space, so someone has to let us in, but you do not have to follow us round. We are happy to talk through what we find at the time, or to arrange a site visit afterwards to go through the report and proposal in person.