Greater London · England
Sand mastic for sash & case windows in Southborough, Greater London
Sand mastic in Southborough from a team with over 20 years’ experience. Rated 4.9 on Google from 180+ five-star reviews.
- Old cement repairs round a window that have failed
- Old sand mastic that has cracked, crumbled or fallen out
- Mastic round period door frames that has failed
Sand mastic in Southborough
A silicone bead around a sash window can look out of place and isn’t always the right material. Sand mastic gives a finish that matches the age of the house and we can swap the silicone for it. Typical jobs include old cement repairs round a window that have failed and draughts and rain around sash boxes, across timber door frames, stone surrounds and sash and case windows.
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.
You get a one-year guarantee, the same in Southborough as everywhere else we work.
- Where
- Southborough (BR2, BR1)
- Region
- Greater London
- Cover
- A year, on every job
- Quotes
- Quoted before any work starts
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
Questions from Southborough
Is parking an issue for sand mastic in Southborough?
Parking in Southborough, as in most of London, takes a little planning: a visitor permit or a bay close to the door helps a lot.
Do you work for landlords with property near Bickley station?
Yes, landlords and agents are among the people we work for, and several properties can go on one quote. You can call 0345 464 0079 or drop us an email with the details for a clear quote.
Do you work for hotels and businesses?
Yes, regularly. Larger jobs can be planned room by room or area by area.
Where is Mr Mastic based?
We are a Crawley-based firm, with over 20 years’ experience. We work across South East England, London and Scotland.
Do you cover Southborough?
Yes. From our base in Crawley, we cover South East England, London and all of Scotland, Southborough included.
When will the new mastic be hard?
Not right away. The skin forms first, and the full set comes later, and we will tell you what to expect.
Do the sealants smell?
It depends on the product. Some products have a noticeable smell, others very little.
Can you match the sealant colour?
Most of the time, yes. We’ll tell you which colours the right product comes in and agree one before we start.
Should I try it myself first?
If you are set on DIY, put the effort into preparation: remove every trace of old sealant, clean and dry the joint, and follow the product’s cure time. If it doesn’t work out, we can still put it right.
A careful DIYer can reseal a simple joint, like a short, easy-to-reach joint indoors. The common mistakes are sealing over old sealant, sealing a damp joint and using far too much.
Also near Southborough
What else we do in Southborough
Honest limits
We’d rather tell you now than do work that won’t last, so here’s what sealant cannot put right:
- Masonry that needs repairing
- Decisions on consent for listed homes
- Cracked or broken glass
If you are not sure, just ring 0345 464 0079 or send us an email and we will give you a straight answer.
Surfaces we seal
- Stone surrounds
- Sash and case windows
- Timber door frames
- Period & listed homes
- Brick reveals
- Tenement windows
Signs you need sand mastic in Southborough
Age is the main cause. Even well-laid mastic needs renewing in time and how long it lasts depends on the weather it faces.
Common reasons people contact us are:
- Mastic round period door frames that has failed
- Modern sealant on a period surround
- Failed mastic on an exposed elevation
- Old cement repairs round a window that have failed
Southborough is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book.
Comparing quotes
- What the cure time is
- Are they insured?
- Whether VAT is included
- What product goes in the joint
Why it’s worth doing now in Southborough
Before painting the windows, it pays to renew the mastic. Paint over cracked mastic won’t stop the gaps and traditional guidance is to leave the new mastic unpainted. Converted houses in London often have a bathroom above someone else’s living room, and a slow leak from a failed seal can end up in the flat below. Dealing with it early is far simpler for homes in Southborough.
Instead of a standard rate, we look at what your job involves: how many joints, what’s in them now and how we reach them. The price is agreed before we begin.
Why us?
- ARBOMaster approved applicator
- One-year guarantee on every job
- Old sealant always removed completely
- Tidy, careful work
See how sealant jobs are priced and our reviews.
How we quote for sand mastic
Every job gets its own quote. These are the things that affect it:
- When we can work, for business premises
- How much old sealant there is and how hard it is to remove
- How easy the joints are to reach
- The number of rooms or windows
A failed joint rarely gets cheaper to fix by waiting, because water and mould keep working on it. If you’re not sure whether it needs doing, phone 0345 464 0079 or email us and we will give you an honest view and a quote.
What to tell us for a quote
Before you ask for a quote, have a think about:
- The type of property
- Where the property is
- What the problem is, such as mould, gaps, leaks or cracking
- Pictures of the joints, sent by email
To get a quote, ring 0345 464 0079 or send us an email and tell us where the job is and what the problem looks like. We will give you a clear quote before any work starts.
For landlords and businesses
In hotels, rooms out of use cost money, so we plan the work room by room around your bookings where we can. We have worked in hotels as well as homes and businesses.
Water getting past a failed joint can damage the building, which matters even more when someone else lives there. Keeping joints in good order is simple maintenance that we can handle for you.
What we do, step by step
Before we leave, we go over the finished joints with you. The work normally takes a few hours for a single window, longer for several, depending on the size of the job. For a job in Southborough, parking and access are the things to plan: let us know about parking, the floor we will be working on and any lift or shared entrance.
- Each surround is checked first.
- We rake out the old mastic and clean the joint.
- Large voids are packed out.
- We point the joint with sand mastic by hand.
- We finish the mastic to a tidy line.
Before we arrive
- Let us know about earlier repairs to the joints
- Let us know about parking restrictions
- For indoor joints, keep the area dry beforehand if you can
Ask for a quote
If you’re in Southborough and need sand mastic, ring 0345 464 0079 or send us an email. A short description of the job and where it is helps us quote, and you will get a clear quote before we start.
Read more
Southborough homes and the weather
In a converted house or block, who looks after the windows depends on the lease, so it’s worth checking before booking. With historic houses such as Bromley Palace (about 1.4 miles north-west) nearby, there’s older building stock in the area around Southborough as well as newer homes. 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.
For site and facilities teams at buildings such as Southborough Primary School, larger buildings have plenty of frames, and the mastic around each one ages. If you let a flat or house near Bickley station, any sash windows need sound mastic to keep draughts and rain out.
Southborough is about 2 miles south-east of Bromley, in Greater London. If you need sand mastic in Southborough, it’s easy to get a quote: please phone 0345 464 0079 or send us an email. We cover Greater London from our Crawley base. Across Greater London, we cover 764 places, Southborough among them. We also work in London, around 10 miles away.
Jobs for sand mastic in BR2 and BR1 works the same way as everywhere else we cover. Whether your property is on Pope Road, Crown Lane and Union Road or anywhere close by, we can help. Other places close to Southborough include Bromley Common (1 mile south-west), Petts Wood (1 mile east), Locksbottom (2 miles south-east), Shortlands (2 miles west) and Crofton (2 miles south-east). Larger places within reach include London (10 miles north-west), City of Westminster (12 miles north-west), Marylebone (12 miles north-west), Kensington (13 miles north-west), St Pancras (12 miles north-west) and Shoreditch (11 miles north-west).
Near you in Southborough
Locally, jobs take us to homes and businesses close to Bishop Justus CofE School, Jubilee Country Park and The Chequers Public House, among other places. For rail, the closest station is Bickley station, roughly 0.7 miles north. Well-known places in the area include Bethlem Museum of the Mind (0.9 miles south-west) and Bridgeways Day Hospital (less than half a mile south). For a walk, there’s Summer Hill and Downham Woodland Walk.