West Sussex · England
Crosspost Sand Mastic
Sand mastic for Crosspost and the surrounding area: careful preparation, the right product and tidy work. Ask us for a quick quote.
- Wind and rain getting in round a sash window
- Mastic that needs renewing before redecorating
- Crumbling sand mastic round a window
Crosspost homes and the weather
Historic houses like Ockenden Manor (about 3.1 miles north-east) are a reminder that the area around Crosspost 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 is traditional sand mastic. Rainfall in the South East is lower than in much of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
Rented homes near Wivelsfield station change hands often, and any sash windows need sound mastic to keep draughts and rain out. If you live in an older home near St Mary Magdalene's Church, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Crosspost is about 4 miles north-west of Burgess Hill, in West Sussex. Whether you are in the middle of Crosspost or further out, we cover sand mastic for every kind of property, from flats and houses to offices and hotels. Our area takes in 371 places across West Sussex, from the larger towns to small villages. Crawley is on our list too, around 9 miles away.
All of RH17 is within our area for sand mastic, from the main roads to the quietest streets. We cover properties on Cowfold Road and Chapel Road and the roads around them. We also cover Bolney (1 mile north-east), Twineham Green (1 mile south), Twineham (2 miles south), Wineham (2 miles south-west) and Kent Street (2 miles west). Within a short drive, we also cover Crawley (9 miles north), Horsham (7 miles north-west), Worthing (14 miles south-west), Haywards Heath (5 miles east), Burgess Hill (4 miles south-east) and East Grinstead (13 miles north-east).
Near you in Crosspost
For rail, the closest station is Wivelsfield station, roughly 4.2 miles east. Other landmarks nearby include The Dene Hospital (2.5 miles south-east) and Cuckfield Museum (3.2 miles north-east). Not far away are Blunts Wood and Paiges Meadow.
About our sand mastic in Crosspost
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. If you are dealing with mastic round period door frames that has failed and open joints round the window box, we can help, on brick reveals, sash and case windows and timber door frames alike.
In a village or hamlet like Crosspost, older cottages and farmhouses often have timber windows set in stone or brick. Older buildings like these do not always suit modern silicone, and sometimes a traditional sand mastic is the better choice.
We stand behind the work with a 12-month guarantee, so you’re covered after we have gone.
- Place
- Crosspost (RH17)
- Region
- West Sussex
- Cover
- One year on every job
- Quotes
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
Surface by surface
Brick reveals
An open joint at a brick reveal lets weather in. New mastic seals the gap.
Stone surrounds
We take care not to mark the stone when the old mastic comes out.
Towns and villages near Crosspost
Other services in Crosspost
Signs you need sand mastic in Crosspost
Over the years, sand mastic weathers. It hardens, cracks and starts to come away on the stone or timber.
Look out for these signs:
- Patchy fillers round a sash window
- Mastic round period door frames that has failed
- Modern sealant on a period surround
- Draughts and rain around sash boxes
Schools such as Bolney CofE Primary School are buildings too, and larger buildings have plenty of frames, and the mastic around each one ages.
Comparing quotes
- How the surfaces are prepared before sealing
- Is the old sealant removed completely?
- Is VAT in the price?
- What insurance they hold
Leave it or put it right?
Cement-based fillers and modern sealants don’t always suit a period surround. Sand mastic matches what was there and that can be important for listed homes. Older cottages and farmhouses around Crosspost 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, as water and mould keep getting in. If you’re not sure whether it needs doing, call 0345 464 0079 or email us and we’ll give you an honest view and a quote.
Why book with us
- An ARBOMaster approved applicator
- One-year guarantee on every job
- Tidy, careful work
- Homes, businesses and hotels
Take a look at our cost guide or our reviews.
The process
On the day, there’s very little for you to do. Point us to the joints and we will get on with it. The job generally takes a few hours per window, depending on the condition of the joints. Somewhere as small as Crosspost, access is often the only tricky part. For outside work, also let us know about exposed walls and any outbuildings involved.
- We check the window surrounds and agree which joints need renewing.
- We rake out the old mastic and clean the joint.
- Large voids are packed out first, so the mastic isn’t too thick.
- The mastic is mixed, pressed into the joint by hand and shaped.
- We dress the surface so it sits neatly against the masonry.
How to prepare
- Tell us about access, such as stairs, a lift or high-level joints
- Tell us if parking is tricky
- For indoor joints, keep the area dry beforehand if you can
Get a quote
For a quote, ring 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
Work for landlords, hotels and businesses
Housing providers, facilities teams and property managers book us too. We can quote a run of properties together.
Failed sealant is one of the commonest items on a check-out report, and it’s easy to sort out between tenants. Several properties can go on one quote.
FAQs for Crosspost
Is Crosspost within the area you cover?
Yes. Crosspost is within the area we cover, which takes in towns, villages and rural addresses. Our work covers London and the South East. Just mention lanes, gates or anything else about the route when you book.
Can you help a landlord with a rental near Wivelsfield station?
Yes, rental work is part of what we do. You can call 0345 464 0079 or send us an email with the address and a few details, and we will give you a fixed price before we start.
What do you put in the joint?
It depends on the joint: anti-fungal sanitary silicone in wet areas, and other sealants where joints move or face the weather. We use products from Arbo and Everbuild.
How long does sand mastic take?
That depends on how much there is to do, but as a guide it takes anything from a few hours to a full day, depending on how many windows. We will give you a better idea when we quote.
Are you an approved applicator?
Yes. We’re approved under the ARBOMaster scheme, the approved applicator scheme for Arbo sealants.
Can you work on commercial sites?
Yes. We work in offices, washrooms, hotels and other commercial premises, as well as homes. Working times can be discussed when we quote.
When will the new mastic be hard?
Not right away. It skins first and hardens fully later, and we will tell you what to expect.
Should I try DIY first?
Some simple jobs can be done by a careful DIYer. The usual mistakes are sealing over old sealant, sealing a damp joint and using too much.
DIY versus a professional finish
The biggest DIY mistake is sealing over old sealant. New silicone will not bond to old, so it peels away and traps moisture behind it. All the old material has to come out first.
If you’ve already had a go yourself, that’s fine. We remove it and do the joint properly, so just mention it when you contact us.
Looking after it afterwards
Joint life depends on how it’s used and looked after. Here’s what we suggest:
- Avoid heavy scraping on the mastic joint
- Keep sills and gutters clear so water drains away
- Renew mastic before redecorating the windows
- Look over the window mastic once a year
Look at the mastic when you look over the windows. Small cracks are easier to deal with early.
An open joint round the box lets weather through. Left, the gap tends to get bigger as more mastic falls out.