West Sussex · England
Sand mastic for sash & case windows in River, West Sussex
Traditional burnt sand mastic around sash and case windows and doors in stone and brick in River, with a one-year guarantee on every job. Ask us for a quote.
- Mastic round period door frames that has failed
- Weathered mastic on the most exposed windows
- Draughty sash windows at the surround
About our sand mastic in River
Traditional burnt sand mastic that sits naturally against stone and brick. It suits period and listed homes, where modern sealant can look out of place. We work on timber door frames, brick reveals and tenement windows, and common reasons people get in touch are weathered mastic on the most exposed windows and open joints round the window box.
Mastic can only go onto a dry, clean joint, so window work in River is booked around the forecast. Tell us about access to every side of the house, including upper-floor windows.
Our work is backed for twelve months, in River and everywhere else we cover.
- Place
- River (GU28)
- Region
- West Sussex
- Cover
- 12 months on all our work
- Quote
- A clear quote up front
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
Can I do it myself?
If you’re set on DIY, put the effort into preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it fails, we can still redo it.
What a professional job adds is preparation and the right product. We take joints back to clean, dry surfaces, and the sealant is matched to the joint and its conditions, then guaranteed for a year.
Common problems we fix in River
Age is the main cause. Sand mastic is a maintenance item like any pointing, depending on exposure and upkeep.
People usually contact us when they notice something like this:
- Silicone on a period window that looks wrong
- Cracked mastic round a front door frame
- Failed mastic on an exposed elevation
- Window mastic to renew ahead of painting
In and around River, as anywhere, good sand mastic starts with a clean, dry, properly prepared joint.
Comparing quotes
- How the colour is chosen
- Whether they’re fully insured
- How the joint is cleaned and prepared
- The length of the guarantee
Quotes for sand mastic in River
The quote reflects the job in front of us. We take into account:
- Any working-time requirements on site
- Whether old sealant or filler has to be cut out
- The number of rooms or windows
- Any mould that needs treating
Doing several joints on one visit is normally more efficient than separate visits, so it’s worth mentioning everything you’d like done. You’ll get one clear quote for the whole job.
What we need to know
You don’t need to know the technical terms. Just tell us:
- Photos by email, if that is easy
- What the problem is, such as mould, gaps, leaks or cracking
- Roughly how big the job is
- Whether it has been sealed before
For a quick quote, get us on the phone, or send an email if you’d rather. Tell us about the joints that need doing and we will talk you through the work before giving you a price.
What we do, step by step
We bring everything the job needs with us, so you don’t need to buy or prepare anything. Once we’ve agreed what’s being done, the area is protected and the work begins. Most jobs take a few hours for a single window, longer for several. For a village or hamlet like River, the journey is planned in advance: let us know about lanes, gates and parking. 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 is not too thick.
- New sand mastic is applied and shaped by hand.
- We finish the mastic to a tidy line.
Preparing for the visit
- Tell us if parking is tricky
- Mention any tricky access
- Let us know if you’ve seen damp or leaks
How to get a quote
To get a quote, phone 0345 464 0079 or send us an email with the location and a short description of the problem. You’ll have a clear quote before work begins.
Read more
Landlords, agents and businesses in River
From a single let to a portfolio, you get the same standard of work: old sealant fully removed, joints prepared properly and a 12-month guarantee.
Failed sealant is one of the commonest items on a check-out report. Several properties can go on one quote.
Also in River
River homes and the weather
Historic houses like Petworth House (about 2.4 miles east) are a reminder that the area around River has older buildings as well as new. Where a home is older, older frames set in brick or stone need a sealant that suits them, and sometimes that’s 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.
For an older house near a landmark such as The Parish Church of St Peter, frames set in older brick or stone need a sealant that suits the wall as well as the frame.
River is about 12 miles east of Petersfield, in West Sussex. Anywhere in GU28, our applicators can take on sand mastic. Our West Sussex coverage runs to 371 places, and River is one of them. There’s also a page for Crawley, roughly 22 miles from River.
Here we cover the GU28 postcode area for sand mastic. Close by, we work in Upperton (1 mile east), Selham (2 miles south), Tillington (2 miles south-east), South Ambersham (2 miles south-west) and Hampers Green (2 miles east). Larger places within reach include Bognor Regis (14 miles south), Chichester (12 miles south-west), Littlehampton (14 miles south-east), Rustington (15 miles south-east), Storrington (11 miles south-east) and Billingshurst (9 miles east).
Around River
In River, that means homes and buildings near The Hollist Arms Public House. Nearby you’ll also find Lodsworth Castle (1.3 miles south) and Coultershaw Heritage Site (3 miles south-east). For a walk, there’s Graffham Common and Blackdown.
Common questions in River
What guarantee comes with sand mastic in River?
Every job comes with our one-year guarantee, wherever it is. We are also fully insured and ARBOMaster approved.
Do you cover River for sand mastic?
Yes, River is within the area we cover. We work across London and the South East. You can ring 0345 464 0079 or email us and let us know what needs doing, and we will give you a clear quote.
Where is Mr Mastic based?
We’re based in Crawley, and we cover South East England, London and all of Scotland.
Are you ARBOMaster approved?
Yes. We hold ARBOMaster approved applicator status, and we are fully insured.
Do I have to be there?
We need access to the joints, so we will agree that with you when we book. For inside work, that normally means someone being in.
Do the sealants smell?
Some sealants have a smell while they cure, which fades as it sets. Ventilation helps.
Can I do it myself?
For a simple, easy-to-reach joint, a careful DIYer can do a reasonable job. The usual mistakes are sealing over old sealant, sealing a damp joint and using too much.
How long does sand mastic take?
Most jobs take a few hours for a single window, longer for several, including preparation and clearing up. Your quote will say how long we expect yours to take.
Why act early in River
Not every draught comes from the sashes themselves. Gaps between the frame and the wall can be just as bad, and renewing the mastic closes them. Older cottages and farmhouses around River can have timber floors and frames, where water from a failed joint can cause rot if it’s left.
A failed joint rarely gets cheaper to fix by waiting, because water and mould keep working on it. If you are unsure, phone 0345 464 0079 or drop us an email and we’ll give you an honest view and a quote.
What you get with us
- Over 20 years’ experience
- ARBOMaster approved applicator
- Neat joints and a tidy finish
- Any old sealant cut out fully, not covered over
Read how sealant jobs are priced and customer reviews.
How to look after the new joints
Looking after new joints is easy:
- Have rotten timber repaired before new mastic goes in
- Sort the mastic before the decorators arrive
- Avoid patching sand mastic with silicone
- Make sure water runs off the sill
Keep paint scrapers and sanders off the mastic when redecorating. It can be damaged by heavy scraping.
Sound mastic protects the frame. Failed mastic lets water reach the timber and timber that stays wet can rot.