Hertfordshire · England
Window & door mastic in Allen's Green, Hertfordshire
Window mastic across Allen's Green and nearby, with every bit of old sealant taken out first and a 12-month guarantee.
- Black, perished sealant on frames
- Cold air getting in at the frame edge
- Water coming in at the bottom corners of a door
How we handle window mastic in Allen's Green
A cold draught around a closed window often comes from the frame edge. Resealing that joint can make a room feel noticeably less draughty. If the draught is through the window seals instead, we’ll tell you. We are often asked to deal with leaking joints at the ends of sills and hard, cracked sealant around windows, on timber windows & doors, uPVC windows and window sills.
In a village or hamlet like Allen's Green, older cottages and farmhouses often have timber windows set in stone or brick. Not every older frame suits a modern silicone bead, and sometimes a traditional sand mastic is the better choice.
Every job comes with a one-year guarantee, wherever you are in Hertfordshire.
- Where
- Allen's Green (CM21)
- Wider area
- Hertfordshire
- Guarantee
- One year on every job
- Quote
- A clear quote up front
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
Can I do it myself?
Some sealant jobs are within reach of a careful DIYer, such as a straightforward joint indoors. The common mistakes are sealing over old sealant, sealing a damp joint and using far too much.
The biggest DIY mistake is sealing over old sealant. Silicone doesn’t stick to old silicone, so it lifts and traps water and mould underneath. Everything old must be removed first.
Also near Allen's Green
Other services in Allen's Green
How to look after the new joints
No joint lasts for ever, but care makes a real difference. Our tips:
- Keep jet washers away from the mastic
- Paint up to the joint, not over it
- Clear any debris from frame drain holes
- Look round the frames every year or so
Wipe the frames with soapy water when you clean the windows, and keep solvents and harsh chemicals off the joint.
Water trapped behind a failed joint can start rot in timber frames and sills. Rotten timber needs a joiner, not a sealant, so it pays to reseal before that happens.
How the job changes by surface
Aluminium frames
Aluminium moves with heat, and the frames are often slimmer than uPVC. A tidy bead in anthracite grey, black or a matching colour suits the frame.
Composite doors
If the door itself is draughty, the issue may be the door seals or hinges rather than the frame mastic. We seal the frame and let you know about anything else.
What we are called out for in Allen's Green
On timber frames, paint and putty build up around the joint. Old mastic gets painted over and cracks under the paint, and the wood moves with damp as well as heat.
Look out for these signs:
- Water coming in at the bottom corners of a door
- Mastic that is falling out in pieces
- Hard, cracked sealant around windows
- Whistling draughts around closed windows
If you live in an older home near Former Church of St Anne, replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint.
What to look for in a quote
- Whether they’re fully insured
- How long the guarantee is
- How long to leave it before use
- Which colour the sealant will be
Quotes for window mastic in Allen's Green
Call for a quick quote. The main things that affect it are:
- The number of rooms or windows
- How easy the joints are to reach
- Mould in or behind the old joints
- The size of the job
Some things make a job bigger or smaller: the old material and how easily it comes out, any mould to treat, and whether the work is at height. We take all of that into account in your quote.
Helping us quote
There’s no need for technical detail. Just tell us:
- The type of property
- Photos by email, if that’s easy
- Any access issues, like height or stairs
- If someone has resealed it before
Every job is quoted individually, so start by telling us what you need. Just ring 0345 464 0079 or drop us an email with the details, and pictures are welcome.
How the visit works
At the end, we look at the finished work together. The work normally takes a morning for a couple of windows and a door, depending on the size of the job. In a small place like Allen's Green, access is generally the main thing to plan. If the job is outside, mention outbuildings, exposed walls and how to reach them.
- First, we confirm safe access to each frame.
- All the failed sealant is cut away, along with any loose debris.
- The surfaces are cleaned and left dry.
- Backing rod fills deep voids and the sealant goes in on top.
- The joint is shaped to shed water and the area tidied.
How to prepare
- Clear the area around the work
- Mention any tricky access
- Keep pets and children clear of the area while we work
Getting a quote
For a quick quote, get us on the phone, or email us if that’s easier. Describe what needs sealing and we’ll explain what’s involved before giving you a price.
Read more
Common questions in Allen's Green
Will you come out to Allen's Green?
Yes. Allen's Green is within the area we cover, which takes in towns, villages and rural addresses. We work across London and the South East. Let us know about access, parking and anything unusual about getting there when you book.
Can you do window mastic in Allen's Green?
Yes, Allen's Green is within the area we cover. Our work covers London and the South East. You can call 0345 464 0079 or drop us an email and tell us what needs doing, and we will send you a clear quote.
What should I tell you?
A short description and the location. If we need more, we will ask.
Is there any odour?
There can be a smell while the sealant cures. Opening a window helps.
Do you hold any approvals?
Yes. We’re approved under the ARBOMaster scheme.
Will it make a mess?
Tidy work is part of the job. We protect what’s around the joints.
Do you work for letting agents?
Yes, regularly. We can quote for several properties at once, and between tenancies is a good time for the work.
Where is Mr Mastic based?
Our base is Crawley, with over 20 years’ experience. We work across South East England, London and Scotland.
What window mastic looks like in Allen's Green
Historic houses like Much Hadham Palace (about 2.2 miles north-west) are a reminder that the area around Allen's Green has older buildings as well as new. Where a home is older, older timber frames in brick or stone need a different approach from a modern uPVC window. Compared with the north and west, the South East gets less rain, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
Rented homes near Sawbridgeworth station change hands often, and renewing tired window mastic between tenants heads off draught and damp complaints.
Allen's Green is about 3 miles south-west of Bishop's Stortford, in Hertfordshire. Allen's Green gets the same service as everywhere we cover: old sealant removed completely, careful preparation and a 12-month guarantee. Across Hertfordshire, we cover 381 places, Allen's Green among them. We also work in Chelmsford, about 17 miles from Allen's Green.
Work in CM21 is quoted and booked the same way as anywhere else. Nearby, we also carry out window mastic in Thorley (2 miles north-east), High Wych (2 miles south), Spellbrook (2 miles east), Sawbridgeworth (2 miles south-east) and Thorley Street (2 miles north-east). We also work in nearby towns such as Stevenage (13 miles west), Bishop's Stortford (3 miles north-east), Welwyn Garden City (13 miles west), Hoddesdon (8 miles south-west), Cheshunt (11 miles south-west) and Hatfield (15 miles west).
Near you in Allen's Green
For rail, the closest station is Sawbridgeworth station, about 2.5 miles south-east. Well-known places in the area include Herts and Essex Hospital (3.4 miles north-east) and Harlow Mill (3.2 miles south). Not far away are Thorley Wash nature reserve.
Landlords, agents and businesses in Allen's Green
Letting agents often deal with us directly. Send the address, what’s needed and the access arrangements and we will give you a quote.
Housing providers, facilities teams and property managers book us too. We can quote a run of properties together.