Greater London · England
Sand mastic for sash & case windows in Bromley, Greater London
Sand mastic in Bromley from a team with over 20 years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Draughts and rain around sash boxes
- Old cement repairs round a window that have failed
- Failed mastic on an exposed elevation
About our sand mastic in Bromley
Burnt sand mastic is a traditional material that sits naturally against stone and brick. It suits period and listed homes, where modern sealant can look out of place. If you’re dealing with window mastic to renew ahead of painting and patchy fillers round a sash window, we can help, whatever the surface.
London’s Victorian and Edwardian terraces were built with timber sash windows, and many still have them or their replacements. Whatever is in the opening now, the joint between frame and wall is what keeps the weather out, in Bromley as anywhere.
Your job is guaranteed for a year, as with all our work.
- Location
- Bromley (BR2, BR1, BR6, BR5)
- Region
- Greater London
- Cover
- One year on every job
- Quote
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
How the job changes by surface
Period and listed homes
Materials matter on listed and conservation-area homes. Sand mastic is often the preferred finish.
Stone surrounds
Stone surrounds suit sand mastic well. It finishes to look like part of the surround.
DIY versus a professional finish
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.
Overfilling a joint is a classic DIY mistake. A thick, smeared bead looks untidy and does not move well, and the joint depth matters as much as the finish.
More services for Bromley
Keeping the joints in good condition
After the cure time, these simple habits help:
- Get any rot dealt with first
- Avoid patching sand mastic with silicone
- Renew mastic before redecorating the windows
- Check with your local planning authority if your home is listed
Avoid sealing over the mastic with silicone. If you see a crack, ask us to take a look before trying a quick fix.
An open joint round the box lets weather through. Left, the gap tends to get bigger.
How the visit works
Our applicators work methodically: protect, prepare, seal, tidy. For most jobs that takes a few hours per window, depending on the condition of the joints, and the area is left clean. In a London area like Bromley, the main things to plan are parking and access: let us know about parking, the floor we will be working on and any lift or shared entrance.
- We check each window surround and the condition of the joint.
- The joint is raked out and cleaned.
- Large voids are packed out.
- We point the joint with sand mastic by hand.
- The finish is dressed neatly.
Before we arrive
- Keep pets and children clear of the area while we work
- Clear items away from the joints we’re working on
- For business premises, tell us about site rules or sign-in
How to get a quote
Want a quote for sand mastic? Please ring 0345 464 0079 or send us an email with a few details. We’ll explain what we’d do and give you a clear price before we start.
Advice
Questions from Bromley
Can you do sand mastic in Bromley?
Yes, Bromley is within the area we cover. We work across London and the South East. Just phone 0345 464 0079 or drop us an email with a few details of the job, and we’ll send you a clear quote.
Can parking be tricky for a visit in Bromley?
London parking needs a little planning, so let us know about permits, bays or a driveway when you book. That way the visit can be planned around it.
Can you match the sealant colour?
We help you choose a colour that suits. The product needed can limit the range.
Do I need to be at home?
For indoor joints, yes, someone needs to let us in. After that, you can carry on with your day.
Do I need permission for sand mastic on a listed building?
It’s best to ask your local planning authority first. Sand mastic is often favoured as like for like, but they decide.
Do you work for landlords and businesses?
Yes, often. We can quote for several properties at once.
Will the old sealant be removed?
Always. Sealing over the old bead is the commonest cause of early failure, so we never do it.
How much does sand mastic cost in Bromley?
There’s no set price, as it depends on the job: its size, the old material, access and the product needed. You’ll get a clear quote before any work starts.
Honest limits
New sealant cannot fix everything, and we will tell you before work begins. Sealant won’t put right:
- Decayed frames that need repair
- Sashes that rattle, stick or won’t open
- Damaged stone surrounds
Not sure which it is? You can phone 0345 464 0079 or email us and we will tell you honestly.
What we seal
- Sash and case windows
- Brick reveals
- Stone surrounds
- Tenement windows
- Period & listed homes
- Timber door frames
Do you need sand mastic in Bromley?
Timber frames move with the seasons. The movement cracks the mastic over time.
The problems people usually mention when they call include:
- Silicone on a period window that looks wrong
- Gaps round a timber door in stone or brick
- Crumbling sand mastic round a window
- Mastic worn away on windows facing the weather
Rented homes near Bromley South station change hands often, and cracked sand mastic around sash windows lets in the draughts tenants complain about.
What your quote should include
- What insurance they hold
- What happens if the job turns out different
- Who turns up on the day
- How the surfaces are prepared before sealing
What sand mastic looks like in Bromley
Historic houses like Bromley Palace (about 0.3 miles east) are a reminder that the area around Bromley 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. In London conversions and blocks, the lease decides who is responsible for the frames, so it’s worth checking before booking.
For an older house near a landmark such as Church of St Peter and St Paul, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall. Bromley is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book.
Bromley is about 8 miles south-east of London, in Greater London. Jobs in Bromley get the same care as everywhere else we work: old sealant removed completely, careful preparation and a 12-month guarantee. Bromley is one of 764 places in Greater London we cover. There’s also a page for London, about 8 miles away.
Postcode districts we cover here for sand mastic: BR2, BR1, BR6 and BR5. If you need sand mastic at a property on High Street, Church Road and St Paul's Square or a nearby road, we can help. With the A222 and A223 close by, Bromley is simple for us to get to. We also cover Sundridge (1 mile north-east), Plaistow (1 mile north), Bickley (1 mile east), Widmore (1 mile east) and Downham (2 miles north). Larger places within reach include London (8 miles north-west), City of Westminster (11 miles north-west), Marylebone (11 miles north-west), Kensington (12 miles north-west), St Pancras (10 miles north-west) and Shoreditch (9 miles north-west).
What’s near Bromley
In Bromley, that means homes and buildings near Bullers Wood School for Boys, The Richmal Crompton pub and Church House Gardens and the streets around them. Bromley has its own railway station: Bromley South station. Other landmarks nearby include The Mall (within half a mile east) and Bromley Hospital (under half a mile south-east). Green spaces nearby include Downham Woodland Walk and Summer Hill.
What happens if it’s left?
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. Damp from a failed joint spreads quietly in older London brickwork and timber, and once it shows in Bromley, the repair is bigger than a sealant job.
There are no prices on our website, because the cost depends so much on the job itself. For a quick quote, please call 0345 464 0079 or send us an email.
Why choose Mr Mastic in Bromley
- A 12-month guarantee on all work
- Trusted Arbo and Everbuild sealants
- Anti-fungal sanitary silicone in wet areas
- We never seal over old sealant
Take a look at how sealant jobs are priced or our reviews.