Kent · England
How Green Window Mastic
We cover How Green for mastic around window and door frames, sills and patio doors. Old sealant removed completely, joints prepared properly and every job guaranteed for a year.
- White mastic on grey or black frames
- Draughty joints inside around the window
- Untidy mastic left by window fitters
How we handle window mastic in How Green
Frames and walls don’t move together. Heat and cold make frames grow and shrink against brick or render that hardly moves. That’s why the joint needs a flexible, low-modulus sealant rather than something rigid. Typical jobs include draughts coming in around windows and doors and damp patches on the reveal after heavy rain, on patio & French doors, composite doors and uPVC windows.
Somewhere as small as How Green, older homes often have timber frames set in stone or brickwork. Not every older frame suits a modern silicone bead, so the sealant has to be chosen to suit the building.
Each job carries a 12-month guarantee.
- Location
- How Green (TN8)
- Region
- Kent
- Guarantee
- One year on every job
- Quote
- Quoted before any work starts
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
What affects the cost of window mastic
Your quote is based on your job. We take into account:
- The product the joint needs
- How many areas need sealing
- Whether the work is at height
- Mould in or behind the old joints
A failed joint rarely gets cheaper to fix by waiting. If you’re unsure, phone 0345 464 0079 or drop us an email for an honest opinion and a quote.
Asking for a quote
What to tell us when you ask for a quote:
- What the problem is, such as mould, gaps, leaks or cracking
- The rough size of the job
- Access, such as stairs, a lift or height
- Pictures of the joints, sent by email
Call for a quick quote, or email us if that’s easier. Tell us about the joints that need doing and we’ll explain what’s involved before giving you a price.
When something else is needed
New sealant can’t fix everything, and we’d rather say so up front. It won’t solve:
- Soft or decayed wood in the frame
- Worn gaskets, brush seals or a door that has dropped
- Damp coming through the wall itself rather than the frame joint
If you are not sure, just phone 0345 464 0079 or send us an email and we will give you a straight answer.
Where we work in How Green
- Window sills
- Aluminium frames
- uPVC windows
- Composite doors
- Patio & French doors
- Timber windows & doors
Places near How Green
More services for How Green
DIY sealant or a professional job?
Overfilling a joint is a classic DIY mistake. A thick, smeared bead looks untidy and doesn’t move well, and the joint depth matters as much as the finish.
Sealing over old silicone is the commonest DIY error. Silicone does not stick to old silicone, so it lifts and traps water and mould underneath. All the old material has to come out first.
Aftercare tips
After the cure time, these simple habits help:
- Clean frames with a soft cloth and soapy water
- Keep drainage slots and sill grooves clear
- Walk round the house once a year and look at the joints
- Ventilate rooms so frames do not stay wet inside
Timber frames need their paint kept up, since wood that gets wet swells and shrinks more. Paint up to the joint, not over the silicone.
Leaks generally show up in wet, windy weather, but resealing works best in dry conditions. Dealing with it when you first notice a crack avoids chasing leaks through the wet months.
Common questions in How Green
Is How Green in your area for window mastic?
Yes. Our work covers London and the South East, and How Green is part of that. Just ring 0345 464 0079 or send us an email with a few details of the job.
I let a flat near Hever station. Can you help?
Yes. We work for landlords and agents as well as householders. You can phone 0345 464 0079 or drop us an email with the details for a clear quote.
Is it messy?
Not at all. The area is protected while we work and cleaned up afterwards.
Can you work on commercial sites?
Yes, regularly. We can plan bigger jobs in stages.
Do the sealants smell?
It depends on the product. Some smell for a while, some hardly at all, and any smell fades as they cure.
What sealant do you use?
The product depends on the job: sanitary silicone where it gets wet, and sealants suited to movement or weather elsewhere. We use products from Arbo and Everbuild.
Can you quote for more than one area?
Yes. Tell us about everything you’d like done.
Do you take out the old sealant first?
Yes. Sealing over the old bead is the commonest cause of early failure, and it’s something we never do.
Landlord and commercial work in How Green
Letting agents and landlords in How Green can book us as well as householders. Resealing between tenancies is a simple way to keep a property in good order before the next move-in.
Hotels need rooms back in use, so the work can be planned room by room. Hotel work is part of what we do, alongside homes and businesses.
Why act early in How Green
Choosing the product is half the job. Decorators’ caulk and bathroom silicone aren’t designed for outside joints that move. An exterior, low-modulus sealant stays flexible in sun and frost. Older cottages and farmhouses around How Green can have timber floors and frames, where water from a failed joint can cause rot if it’s left.
What you pay reflects the work, not guesswork. That’s why we ask a few questions first.
Why us?
- We are fully insured
- Trusted Arbo and Everbuild sealants
- A 12-month guarantee on all work
- We agree the colour with you first
Windows and doors in How Green
Historic houses like Hever Castle (about 0.7 miles south) are a reminder that the area around How Green has older buildings as well as new. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that is traditional sand mastic. Compared with the north and west, the South East gets less rain, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
Schools such as Hever Church of England Voluntary Aided Primary School are buildings too, and the mastic around its windows and doors needs looking after like any other building’s. For landlords with property near Hever station, renewing tired window mastic between tenants heads off draught and damp complaints. In the older streets around Church of St Peter, frames set in older brick or stone need a sealant that suits the wall as well as the frame.
How Green is about 7 miles south-west of Sevenoaks, in Kent. Anywhere in TN8, our applicators can take on window mastic. How Green is one of 922 places in Kent we cover. We also work in Crawley, around 14 miles away.
All of TN8 is within our area for window mastic, from the main roads to the quietest streets. We cover properties on Hever Road and How Green Lane. We also cover the places around How Green: Hever (1 mile south), Newtown (2 miles south), Markbeech (2 miles south), Chiddingstone Causeway (3 miles east) and Chiddingstone Hoath (3 miles south-east). We also work in nearby towns such as Sevenoaks (7 miles north-east), Royal Tunbridge Wells (8 miles south-east), Tonbridge (7 miles east), Swanley (14 miles north), Kings Hill (14 miles east) and Paddock Wood (12 miles east).
What’s near How Green
In How Green, that means homes and buildings near The Wheatsheaf Public House and Chiddingstone Castle Park and Gardens. The nearest railway station is Hever station, about 1.3 miles south-west of the centre. A little further out are Tandridge Priory (5.4 miles north-west) and Hever Castle (0.7 miles south).
What we do, step by step
You don’t need to clear the whole room or building before we come, just the space around the work. We protect the rest, and the job takes most of a day for a typical house, less for a few frames in most cases. For a village or hamlet like How Green, the journey is planned in advance: let us know about lanes, gates and parking. Everything for the job comes with us, so a second trip is avoided where possible.
- First, we confirm safe access to each frame.
- Old, cracked mastic is removed completely, along with any loose debris.
- The surfaces are cleaned and left dry, and primed where the sealant calls for it.
- Backing rod fills deep voids and the sealant goes in on top.
- We tool the joint so water runs off, then clear up.
How to prepare
- Mention any leaks or damp you’ve noticed
- Clear the area around the work
- Tell us about access, such as stairs, a lift or high-level joints
Get a quote
Want a quote for window mastic? Please phone 0345 464 0079 or email us with a few details. You will know what we plan to do, and what it will cost, before any work begins.