West Sussex · England
Washington Sand Mastic
Professional sand mastic in and around Washington, with every bit of old sealant taken out first and a 12-month guarantee.
- Weathered mastic on the most exposed windows
- Gaps where the frame meets the masonry
- Mastic that needs renewing before redecorating
Leave it or put it right?
Draughts round a sash window are not always the sashes. Gaps between the frame and the wall can be just as bad and new mastic seals them. Around Washington, older homes often have timber in their floors and frames, and water through a failed joint can rot timber if it’s left.
Leaving a failed joint usually makes the job bigger, not smaller, as water and mould keep getting in. If you’re unsure, call 0345 464 0079 or email us for an honest opinion and a quote.
Why Washington clients choose us
- Arbo and Everbuild products
- We’re fully insured
- A 12-month guarantee on all work
- ARBOMaster approved applicator
Read what affects the cost and our reviews.
Sand mastic in Washington, done properly
For a listed home or one in a conservation area, ask your local planning authority whether consent is needed for work to windows. Like-for-like sand mastic is often the preferred finish. We work on timber door frames, period & listed homes and sash and case windows, and people most often call us about patchy fillers round a sash window and cracked mastic round a front door frame.
Mastic can only go onto a dry, clean joint, so window work in Washington is booked around the forecast. Tell us about access to every side of the house, including upper-floor windows.
Each job carries a 12-month guarantee.
- Where
- Washington (RH20)
- Wider area
- West Sussex
- Cover
- 12 months on all our work
- Quotes
- A clear price before we start
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
What sand mastic looks like in Washington
Historic houses like Parham House (about 3.9 miles west) are a reminder that the area around Washington 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’s traditional sand mastic. London and the South East are among the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
For an older house near a landmark such as The Parish Church of St Mary, frames set in older brick or stone need a sealant that suits the wall as well as the frame.
Washington is about 6 miles north of Worthing, in West Sussex. For sand mastic in and around Washington, it’s easy to get a quote: please phone 0345 464 0079 or drop us an email. We cover West Sussex from our Crawley base, Washington included. Our area takes in 371 places across West Sussex. For nearby work, see our Brighton page.
All of RH20 is within our area for sand mastic, from the main roads to the quietest streets. Local streets include London Road, The Street and Chanctonbury Close, all of which we cover. We also cover the places around Washington: Rock (1 mile north), Sullington (1 mile west), Heath Common (2 miles north-west), Storrington (2 miles north-west) and Warminghurst (2 miles north). We also work in nearby towns such as Horsham (12 miles north), Worthing (6 miles south), Bognor Regis (15 miles south-west), Haywards Heath (15 miles north-east), Burgess Hill (13 miles east) and Littlehampton (8 miles south-west).
Landmarks near Washington
We work in homes and buildings around Rydon Community College, Windlesham House School and The Frankland Arms Public House, among other places. Well-known places in the area include The Storrington And District Museum (2 miles north-west). Not far away are Chanctonbury Hill.
Towns and villages near Washington
What else we do in Washington
The process
There’s no need to move everything out, just the space around the work. Everything nearby is protected, and the job takes a few hours for a single window, longer for several in most cases. Somewhere like Washington needs a little journey planning: tell us about narrow lanes, gates, long drives and where we can park. We bring what the job needs, so it can be finished in one trip where possible.
- Each surround is checked first.
- We rake out the old mastic and clean the joint.
- We fill deep gaps so the new mastic isn’t too thick.
- New sand mastic is applied and shaped by hand.
- The finish is dressed neatly.
How to prepare
- Let us know about stairs, lifts or work at height
- Let us know if you’ve seen damp or leaks
- Mention any sign-in or site rules at work premises
Get a quote
Call for a quick quote, or email us if that’s easier. Describe what needs sealing and we’ll talk you through the work.
Related advice
Questions from Washington
What guarantee comes with sand mastic in Washington?
All our work, in Washington and everywhere else, comes with a 12-month guarantee. We are fully insured, and an ARBOMaster approved applicator.
Is Washington in your area for sand mastic?
Yes. We work across London and the South East, and Washington is part of that. You can call 0345 464 0079 or email us and let us know what needs doing, and we’ll send you a clear quote.
Can I paint the new mastic?
Sand mastic is normally left unpainted, which is what traditional guidance recommends. Ask us before decorating.
Is it messy?
We keep the work tidy. Nearby surfaces are protected.
How do I get a quote for sand mastic in Washington?
Size, access and the old material all affect the cost. Call for a quick quote and we’ll talk you through it.
Will there be a smell?
Possibly a little. Any smell clears as the sealant cures, and ventilation helps.
Do you have insurance?
Yes. We are fully insured.
Do you do commercial work?
Yes, regularly. Larger jobs can be planned room by room or area by area.
For landlords and businesses
In hotels, rooms out of use cost money, so the work can be planned room by room around your bookings where we can. Hotel work is part of what we do, alongside homes and businesses.
Mouldy or split sealant often shows up at the end of a tenancy, and it’s quick to put right between tenancies. Several properties can be quoted together.
Signs you need sand mastic in Washington
Sand mastic slowly weathers. It dries out, cracks and loses its grip from the frame or the masonry.
Keep an eye out for any of the following:
- Mastic that needs renewing before redecorating
- Mastic worn away on windows facing the weather
- Open joints round the window box
- Gaps round a timber door in stone or brick
Schools such as St Mary's CofE Primary School are buildings too, and larger buildings have plenty of frames, and the mastic around each one ages.
Questions to ask before you book
- What guarantee comes with the work
- How the joint is cleaned and prepared
- Who turns up on the day
- What insurance they hold
When it is not the sealant
We’d rather tell you now than do work that won’t last, so these are the limits:
- Decayed frames that need repair
- Planning or listed building consent (your local planning authority decides)
- Masonry that needs repairing
If you’re not sure, just call 0345 464 0079 or send us an email and we will give you a straight answer before booking.
Surfaces we seal
- Sash and case windows
- Period & listed homes
- Tenement windows
- Stone surrounds
- Timber door frames
- Brick reveals
How the job changes by surface
Sash and case windows
The mastic round a sash window is on show, so a neat, even finish matters.
Period and listed homes
Materials matter on listed and conservation-area homes. Sand mastic is often the preferred finish.
DIY sealant or a professional job?
Too much sealant is as bad as too little. A heavy bead looks messy and copes badly with movement, and getting the depth right matters as much as the look.
A careful DIYer can reseal a simple joint, like a short, easy-to-reach joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.