West Sussex · England
Sand mastic for sash & case windows in Southgate, West Sussex
Problem with your window and door surrounds in Southgate? We remove the old material, prepare the joints and seal them properly.
- Window mastic to renew ahead of painting
- Old sand mastic that has cracked, crumbled or fallen out
- Mastic round period door frames that has failed
How the job changes by surface
Tenement and terrace windows
In shared buildings, the windows may be part of a wider repair, so check who is responsible first.
Period and listed homes
Many older homes were built with sand mastic round the windows. If your home is listed, ask your local planning authority about consent.
How we handle sand mastic in Southgate
Fresh sand mastic forms a skin quite soon, but it takes longer to harden fully. Traditional guidance is not to paint over it and we’ll advise if you are redecorating. We work on stone surrounds, period & listed homes and timber door frames, and common reasons people get in touch are mastic dropping out of the joint and silicone on a period window that looks wrong.
In a smaller place like Southgate, some walls face open ground and catch the full force of the weather, so exposed windows and doors face the weather head on. That’s hard on the mastic around frames and sills.
The work is guaranteed for twelve months. If something is not right with it in that time, tell us and we will put it right.
- Where
- Southgate (RH10, RH11)
- Wider area
- West Sussex
- Cover
- A year, on every job
- Price
- A clear quote up front
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
Why deal with it now?
Draughts round a sash window aren’t always the sashes. Gaps between the frame and the wall can be just as bad and new mastic seals them. Around Southgate, water from a failed joint in an older home can soak into timber and plaster, which is far harder to put right than the sealant itself.
Combining jobs into one visit is usually 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.
Why book with us
- Neat joints and a tidy finish
- Experience in homes, commercial sites and hotels
- Every job guaranteed for a year
- Fully insured
Take a look at how sealant jobs are priced or what customers say.
Looking after it afterwards
Joint life depends on how it’s used and looked after. We suggest:
- Get any rot dealt with first
- Ask the planning authority about consent for listed or conservation-area homes
- Plan mastic work ahead of painting
- Make sure water runs off the sill
Avoid painting over the new mastic, which is the traditional advice. If you’re redecorating, ask us first.
Sound mastic protects the frame. Failed mastic lets water reach the timber and timber that stays wet can rot.
Honest limits
Some problems need a builder, plumber or other trade rather than us:
- Masonry that needs repairing
- Planning or listed building consent (your local planning authority decides)
- Rotten sashes, sills or window boxes (a joiner’s job)
If in doubt, call 0345 464 0079 or drop us an email and we will say what we think.
Where we work in Southgate
- Brick reveals
- Timber door frames
- Tenement windows
- Sash and case windows
- Period & listed homes
- Stone surrounds
How it works
A visit follows a simple pattern: we check the joints, mask and protect the surrounding surfaces, carry out the job and clear up. It usually takes a few hours per window, depending on the condition of the joints. A visit to Southgate is planned like any other: the time, the access and where to park are agreed in advance. If the work is outside, the weather plays a part, as sealant needs a dry surface.
- We start by checking each surround and agreeing the joints to renew.
- The loose and crumbling mastic is raked out and the joint cleaned.
- Deep voids are packed so the mastic is the right thickness.
- The mastic is mixed, pressed into the joint by hand and shaped.
- We dress the surface so it sits neatly against the masonry.
Preparing for the visit
- Let us know if you’ve seen damp or leaks
- Keep children and pets away from the work area
- Mention if the joints have been sealed before
Get a quote
We don’t publish a price list. Instead, we give you a clear quote for your job. To arrange one, ring 0345 464 0079 or email us.
Read more
For landlords and businesses
Letting agents often deal with us directly. Tell us the address, the job and how access works and we’ll quote.
Landlords and letting agents in Southgate 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.
Sand mastic in Southgate: local notes
With historic houses such as Tyes Place (about 5 miles south) nearby, there’s older building stock in the area around Southgate as well as newer homes. In older buildings, 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, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
Homes close to St Mary's include some older properties, and frames set in older brick or stone need a sealant that suits the wall as well as the frame. For landlords with property near Crawley station, cracked sand mastic around sash windows lets in the draughts tenants complain about.
Southgate is about 1 mile south-west of Crawley, in West Sussex. We provide sand mastic to homes and businesses in Southgate and the surrounding area. Across West Sussex, we cover 371 places, Southgate among them.
We cover every part of the RH10 and RH11 postcode area for sand mastic. You will find streets such as Oak Road, Cook Road and Colet Road, and we cover them all. Southgate is on the A2004 and A2219, which makes it straightforward to reach. Neighbouring places we cover for sand mastic include Crawley (1 mile north-east), Tilgate (1 mile east), West Green (1 mile north), Three Bridges (1 mile north-east) and Langley Green (2 miles north). Further out, we also cover Horsham (6 miles south-west), Haywards Heath (9 miles south-east), Burgess Hill (11 miles south), East Grinstead (8 miles east), Billingshurst (13 miles south-west) and Roffey (5 miles south-west).
What’s near Southgate
In Southgate, that means homes and buildings near Three Bridges Junior School, St Wilfrid's Catholic School and Tilgate Park. There’s a railway station in Southgate itself: Crawley station. Well-known places in the area include Crawley Museum (0.7 miles north) and County Mall (0.5 miles north-east). Not far away are Tilgate Lake.
Questions from Southgate
Is Southgate within the area you cover?
Yes, Southgate is covered. We work across London and the South East, and smaller places are part of that. Longer journeys are simply planned in advance.
I let a flat near Crawley station. Can you help?
Yes, we work for landlords and letting agents. Just phone 0345 464 0079 or email us and tell us about the property, and we will give you a clear price.
Can I choose the sealant colour?
Yes. Sealants come in white, clear, grey and other colours for many products, and we’ll agree it with you first.
Is it possible to take out silicone and use sand mastic instead?
Yes, it’s a common request. All the old silicone is removed first so the mastic can sit properly.
Where are you based?
Our base is in Crawley, and we work across South East England, London and Scotland.
Will there be a smell?
Some sealants have a smell while they cure, but it fades. Opening a window helps.
How long does sand mastic take to harden?
A skin forms quite soon, but full hardening takes longer. We’ll tell you what to expect for your job.
Can you work on commercial sites?
Yes. We have worked for hotels, offices and other businesses, and we are fully insured.
Nearby places to Southgate
What else we do in Southgate
What we are called out for in Southgate
Water gets into small cracks in the mastic and pushes it out. Windows facing the weather tend to go first.
The problems people generally mention when they call are:
- Old sand mastic that has cracked, crumbled or fallen out
- Window mastic to renew ahead of painting
- A silicone bead on a sash window that spoils the look
- Old cement repairs round a window that have failed
For site and facilities teams at buildings such as Southgate Primary, the mastic around its windows and doors needs looking after like any other building’s.
Questions to ask before you book
- Whether you can choose the colour
- Whether they seal over old material or remove it
- What preparation is included
- Is VAT in the price?