West Sussex · England
Window & door mastic in Horsham, West Sussex
Our applicators work in Horsham on mastic around window and door frames, sills and patio doors. Old sealant removed completely, joints prepared properly.
- Draughty joints inside around the window
- Draughts coming in around windows and doors
- Mastic that has split away from the wall
Window mastic in Horsham, done properly
A cold draught around a closed window often comes from the frame edge. Resealing that joint can make a room feel noticeably less draughty and quietens the whistle on windy days. Where the air is getting in through the window itself, we’ll say so. If you’re dealing with a bead that doesn’t match the frame and leaking joints at the ends of sills, we can help, on composite doors, uPVC windows and window sills alike.
In Horsham, windows range from older timber frames to modern uPVC and aluminium. The mastic around all of them ages, and it’s normally the first thing to let the weather in.
The work is guaranteed for twelve months. If something isn’t right with it in that time, tell us and we will put it right.
- Place
- Horsham (RH12, RH13, RH20, BN44)
- Wider area
- West Sussex
- Cover
- One year on every job
- Price
- A clear price before work begins
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
When to call us in Horsham
Water runs down the glass onto the sill, and the ends of the sill, where it meets the wall, are where it gets in. Failed sealant there lets rain into the wall or behind the frame.
Common reasons people contact us include:
- Gaps between the frame and the inside reveal
- Untidy mastic left by window fitters
- Mastic that’s falling out in pieces
- Sealant in the wrong colour for the frame
For an older house near a landmark such as Hope Chapel, frames set in older brick or stone need a sealant that suits the wall as well as the frame.
Questions to ask before you book
- Are they insured?
- The length of the guarantee
- Which sealant they’ll use, and why
- Whether they seal over old material or remove it
Honest limits
New sealant can’t fix everything, and we’d rather say so up front. Sealant will not put right:
- Condensation trapped between the panes
- A door that needs adjusting, rehanging or new seals
- A frame that has rotted at the joint
If in doubt, call 0345 464 0079 or send us an email and we’ll say what we think.
Surfaces we seal
- Window sills
- Aluminium frames
- Timber windows & doors
- uPVC windows
- Composite doors
- Patio & French doors
FAQs for Horsham
Is Horsham in your area for window mastic?
Yes. We work across London and the South East, and Horsham is part of that. Just call 0345 464 0079 or drop us an email with a few details of the job.
Is window mastic in Horsham guaranteed?
All our work, in Horsham and everywhere else, comes with a 12-month guarantee. We’re also fully insured and ARBOMaster approved.
Do you work for letting agents?
Yes, often. We can quote for several properties at once, and between tenancies is a good time for the work.
Should I try DIY first?
You can, for simple jobs. The key is preparation: remove all the old material and work on a clean, dry joint. If it does not work out, we can redo it.
Do you work for hotels and businesses?
Yes. We have worked for hotels, offices and other businesses.
Do you have insurance?
Yes. Mr Mastic is fully insured, with over 20 years’ experience in sealant work.
Can you reach windows above the ground floor?
Yes, if safe access is possible. For high or awkward windows, we will tell you what access is needed.
Can you get sealant to suit coloured frames?
Yes. Grey and black frames get grey or black sealant, and wood-effect frames usually suit brown.
How to look after the new joints
How long the joints last depends on use and care. Here’s what we suggest:
- Keep drainage slots and sill grooves clear
- Do not use solvent cleaners on the joint
- Keep jet washers away from the mastic
- Check the mastic once a year
Try not to touch the new joint while it cures, following the cure time we give you. Keep jet washers away from the frames.
Leaks usually show up in wet, windy weather, but sealant goes on best when frames and walls are dry. Dealing with it when you first notice a crack avoids chasing leaks through the wet months.
Window mastic in Horsham: local notes
The South East is one of the drier parts of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
For landlords with property near Horsham station, sound mastic around windows and doors keeps out the draughts and damp that tenants notice first.
Horsham is about 31 miles south of London, in West Sussex. For window mastic in and around Horsham, it’s easy to get a quote: please phone 0345 464 0079 or send us an email. We are based in Crawley and cover West Sussex, Horsham included. Across West Sussex, we cover 371 places, Horsham among them. For nearby work, see our Crawley page, about 7 miles away.
Postcode districts we cover here for window mastic: RH12, RH13, RH20 and BN44. Whether your property is on Station Road, London Road and Market Square or anywhere close by, our applicators can take on the job. Horsham is on the A24 and A29, so it’s easy for us to get to. We also cover the places around Horsham: Tower Hill (1 mile south-west), Broadbridge Heath (2 miles west), Holbrook (2 miles north), Warnham (2 miles north-west) and Southwater (3 miles south). Larger places within reach include Crawley (7 miles north-east), Haywards Heath (11 miles south-east), Burgess Hill (11 miles south-east), East Grinstead (14 miles east), Broadfield (5 miles east) and Storrington (11 miles south-west). As one of the bigger places in West Sussex, Horsham has every kind of property, from flats to offices.
Landmarks near Horsham
Locally, jobs take us to homes and businesses close to Millais School, Warnham Park and Kingslea Primary School. Horsham has its own railway station: Horsham station. Well-known places in the area include Christs Hospital School Museum (2.4 miles south-west) and Horsham Hospital (less than half a mile north-west). The countryside around Horsham includes Warnham LNR.
Why it’s worth doing now in Horsham
Running fresh sealant over the old joint is tempting, but new sealant can’t bond to old, crumbling mastic. It peels before long, and water still gets in behind. The old mastic has to come out. For businesses in Horsham, a room closed because of a leak or mould costs more than the sealant, so failing joints are best replaced on a planned basis.
What you pay reflects the work, not a rough estimate. That is why we ask a few questions first and give you a clear price before we start.
Why Horsham clients choose us
- Any old sealant cut out fully, not covered over
- An ARBOMaster approved applicator
- White, clear, grey or coloured to suit, where the product allows
- Anti-fungal silicone where joints get wet
Take a look at how sealant jobs are priced or customer reviews.
For landlords and businesses
Landlords and letting agents in Horsham 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.
Whether it’s one flat or a portfolio, the work is the same standard: old sealant fully removed, joints prepared properly and a 12-month guarantee.
How the visit works
We bring everything the job needs with us, so there’s nothing for you to buy. Once we’ve agreed what’s being done, the area is protected and the work begins. Most jobs take most of a day for a typical house, less for a few frames. Commercial jobs in Horsham can be planned out of hours where a building cannot close, and homes are booked within our usual hours, Monday to Saturday.
- We check each frame and agree which ones need doing.
- The old mastic is cut out and the surfaces cleaned back.
- We fit backing rod in deep gaps so the sealant is the right depth.
- We apply a weatherproof sealant to match the frame and tool it neatly.
- Finally we tidy up and check each joint.
Before we arrive
- Tell us about any previous sealing or DIY attempts
- On commercial sites, let us know about site rules
- Clear items away from the joints we’re working on
Get a quote
For a quote, call 0345 464 0079 or drop us an email with the location and a short description of the problem. We will give you a clear quote before any work starts.
Advice
Also near Horsham
Also in Horsham
How we quote for window mastic
There’s no set price list, because jobs vary so much. What we look at:
- The number and length of the joints
- Mould in or behind the old joints
- The product the joint needs
- Working hours on commercial sites
A failed joint rarely gets cheaper to fix by waiting, as water and mould keep getting in. If you’re unsure, call 0345 464 0079 or drop us an email and we will give you an honest view and a quote.
Helping us quote
The more you tell us, the more accurate the quote. When you ask for a quote, tell us:
- The rough size of the job
- Whether it’s a home or a business
- The address or postcode of the job
- Any previous sealing or DIY work
For window mastic in Horsham, ring 0345 464 0079 or drop us an email. A short description of the job and where it is helps us quote, and you will get a clear quote before we start.