Lee FlecknellEmergency roof repairs, rental property · August 2026
Highly recommend this company carried out some emergency roof repairs on one of my properties would use again.
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Extension roofs and roof timbers
Extension roofs and new roof timbers, built from the frame up
Extension roofs from Best Top Roofing are built from the timber frame up, then membraned, battened and tiled to match the house. We build new pitched and flat roof structures for extensions, garages and gables, and replace rotten or sagging rafters, purlins and wall plates on existing roofs across Hertfordshire and Northamptonshire.
An extension is only as good as its roof, and the roof is where many extensions go wrong: a pitch too shallow for the tile, a valley where the new roof meets the old with nowhere for water to go, or a flat roof with no fall. We build roofs that are right for the covering and tie into the existing house properly, whether that is a pitched roof in tiles to match the house or a flat roof in GRP or EPDM.
The photograph at the top of this page is a new gable roof structure on an extension, framed in new rafters with the gable ladder in place, ready for membrane and battens. We cut and fix rafters, ridge boards, purlins and gable ladders to suit the drawings and the building control inspector, then cover the roof in the material you have chosen, with the lead and flashings where it meets the house.
On existing roofs, timbers fail from long-term leaks, woodworm, overloading with heavier tiles, or simply age. A dip in the ridge or a slope that has gone wavy is often a sign. We replace rotten timbers or strengthen them alongside, usually during a re-roof when the timbers are exposed.
When you call, you speak to the familyBest Top Roofing is family-run. The family that answers the phone and gives you the quote is the family that turns up and does the job.
What is included
- New pitched roof structures for single-storey and two-storey extensions
- Gable ends, gable ladders and ridge boards
- Flat roof joists, firrings and decking
- Rotten or sagging rafters, purlins and wall plates replaced
- Timbers strengthened or doubled up where a roof has spread
- Membrane, battens and tiles to match the house
- Valleys and flashings tying the new roof into the old
Signs you need this
- A ridge line that dips in the middle
- Roof slopes that look wavy from the street
- Rot or woodworm in the loft timbers
- Planning an extension or garage conversion
- A previous extension roof that has always leaked at the joint
Roof timbers and extensions: our recent work
Every photo is one of our own jobs. Tap to enlarge.
Roof stripped to the rafters with new membrane and battens going on above a conservatory
Roofers battening a re-roof around a new roof window over red membrane
Aerial view of a dormer on a re-roof, membrane and battens on, skip in the street
Dormer front in slate with a lead-dressed apron and blue membrane around it
How it works
Plans and survey
We look at your drawings or the existing roof and the building control requirements.
Fixed written price
Timbers, covering and junctions set out in writing.
Frame and cover
Structure built, membrane and battens on, tiles or flat roof laid.
Tie-in and finish
Lead and flashings to the house, fascias and gutters, site cleared.
We build the roof as well as cover it, so the frame, the covering and the tie-in to your house are all done by the same people.
Roof timbers and extensions: your questions answered
Do you work with builders on extensions?
Yes. We build and cover roofs on extensions for homeowners and for builders who want a specialist to take on the roof.
Will the new roof match my house?
We source tiles or slates to match your existing roof as closely as possible. Where an exact match is no longer made, we can use reclaimed tiles or re-tile a slope to blend.
Do extension roofs need building control?
New extensions need building regulations approval, which covers the roof structure, insulation and ventilation. We build to the approved drawings and work with the inspector.
Can sagging roof timbers be fixed without a re-roof?
Some can be strengthened from inside the loft. Where the rafters or purlins have failed badly, the job is done properly with the roof open, usually during a re-roof.
Can you build a dormer roof?
Yes. We build and cover dormer roofs, including the lead cheeks and aprons, in tiles, slate, GRP or EPDM.
Related services
Reviews
What customers say on Google
Dannie SmithQuoted the next day · June 2026
Thomas came and gave me a quote next day, very professional and clean work was carried out. I will be using best top roofing for all my projects going forward and would highly recommend them.
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R Vidya RLeaking felt roof repaired · September 2026
thanks to Thomas for fixing our roof. It was pleasure working with you. I feel confident that the water leak is accessed from all points and all problem addressed
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Lee SextonNew flat roof · April 2026
I needed a new flat roofing doing and this amazing company did it exactly how I wanted it. Highly recommended. Friendly and polite. Would use and again and tell all my friends and family.
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Mahmoud Al SuwwanRoof problem fixed · August 2026
We had a problem in our roof we called this company and they solved the problem so happy and satisfied. I really highly recommend if anyone needs roofing work done if I ever need a roofer again hopefully we don't if I ever did I will always use this company again, thank you so much, guys.
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Lisa DunneBlocked gutters cleared · April 2026
Cleaned out our gutters as were blocked and overflowing. Very happy with the job done. Thank you very much!
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Ligita KaledaiteChosen over other quotes · July 2026
Very friendly. Had couple of Quotes from other companys And this was the best company for it.
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Sally MaskellRoofing work by Thomas · June 2026
Very impressed with the work that Thomas has done. Definitely recommend.
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Scarlet BullRoofing work · August 2026
Professional, good quality work! Recommended.
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Checkatrade customerBalcony roof installation · August 2026
Fantastic, professional and polite throughout the job.
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10 year
re-roof
guarantee
Our guarantee
re-roof
guarantee
Every new re-roof guaranteed for 10 years, in writing
When we replace your roof, our workmanship is guaranteed for 10 years from the day we finish, and the membrane, tiles and slates carry their manufacturers' guarantees on top. Repairs and flat roofs are guaranteed too, with the terms for your job written on your quote. We are fully insured.
Covered
- Our workmanship on every new re-roof for 10 years
- Lead, flashings, ridges and verges we fit
- Flat roofs laid to the system's specification
- Repairs, with the terms written on the quote
On top
- Tile and slate manufacturer guarantees
- Membrane and flat roof system guarantees
- Photos of the finished job
- The same family to call if anything is wrong
Not covered
- Storm or accidental damage after completion
- Work altered or added by someone else
- Parts of the roof we did not work on
- Gutters left to block and overflow
The guarantee for your job is written on your quote before you agree to anything. Read the full guarantee.
Talk to us about roof timbers and extensions
Ring or send the form. We come out, look at the roof, show you what is needed and give you a fixed written price. No pressure and no hidden extras.