Greater London · England
Sand mastic for sash & case windows in Pratt's Bottom, Greater London
Problem with your window and door surrounds in Pratt's Bottom? We cut out the old, prepare the joints and apply the right sealant.
- Mastic that needs renewing before redecorating
- Mastic round period door frames that has failed
- Failed mastic on an exposed elevation
Work for landlords, hotels and businesses
Housing providers, facilities teams and property managers book us too. We can quote a run of properties together, and we’re fully insured for the work.
Mouldy or split sealant often shows up at the end of a tenancy, and it’s easy to sort out between tenants. We can quote for more than one property at once.
Sand mastic for homes and businesses in Pratt's Bottom
Sand mastic has long been used to fill the joint between timber frames and masonry. It’s made from sand and a linseed-oil-based binder, applied by hand. On older homes, it suits the building far better than silicone. We work on tenement windows, sash and case windows and brick reveals, and people most often call us about gaps between timber frames and stone or brick and silicone on a period window that looks wrong.
Much of London’s older housing was built with timber sash windows, some still in place and some long since replaced. Either way, the mastic between frame and brickwork is what stops draughts and rain getting in.
There’s a 12-month guarantee on every job, whatever its size.
- Location
- Pratt's Bottom (BR6, TN14)
- Wider area
- Greater London
- Guarantee
- One year on every job
- Quotes
- A clear price before any work starts
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
Questions from Pratt's Bottom
Is Pratt's Bottom in your area for sand mastic?
Yes. Our work covers London and the South East, and Pratt's Bottom is part of that. You can call 0345 464 0079 or send us an email and tell us what needs doing.
Can parking be tricky for a visit in Pratt's Bottom?
Parking in Pratt's Bottom, as in most of London, takes a little planning: a visitor permit or a bay close to the door helps a lot.
Do you have insurance?
Yes. We’re fully insured for every job we do.
Can I do it myself?
You can, for simple jobs. The key is preparation: remove all the old material and work on a clean, dry joint. We can always put it right if it fails.
Can I add another job to the visit?
Yes. More than one area can go on one quote.
Do you do commercial work?
Yes, regularly. We can plan bigger jobs in stages.
Should I use sand mastic or silicone?
Sand mastic generally suits period timber windows best. Modern frames normally suit a flexible sealant.
Where do you work from?
We work from Crawley. We cover Pratt's Bottom and the rest of Greater London.
Should I try it myself first?
The biggest DIY mistake is sealing over old sealant. Silicone does not stick to old silicone, so it lifts and traps water and mould underneath. Everything old must be removed first.
Not every job suits DIY: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.
Nearby places to Pratt's Bottom
What else we do in Pratt's Bottom
Frames and glazing around Pratt's Bottom
In London conversions and blocks, the lease decides who is responsible for the frames, so it’s worth checking before booking. 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.
Managing a site like Pratts Bottom Primary School? Then the mastic around its windows and doors needs looking after like any other building’s. Homes close to All Souls' Church include some older properties, and the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Pratt's Bottom is about 3 miles south of Orpington, in Greater London. We carry out sand mastic for householders, landlords and businesses in Pratt's Bottom and nearby. 764 places in Greater London are on our list. Our London page covers work nearby, about 14 miles away.
Here we cover the BR6 and TN14 postcode area for sand mastic. Whether your property is on Orchard Road, Runciman Close and Downs View Close or a nearby road, our applicators can take on the job. Other places close to Pratt's Bottom include Halstead (1 mile south-east), Chelsfield (1 mile north-east), Bopeep (1 mile north-east), Badgers Mount (1 mile east) and Maypole (1 mile north-east). We also work in nearby towns such as London (14 miles north-west), Shoreditch (15 miles north-west), Whitechapel (14 miles north-west), Stockwell (13 miles north-west), Orpington (3 miles north) and Wimbledon (15 miles west).
Around Pratt's Bottom
In Pratt's Bottom, that means homes and buildings near Hewitt's Chalk Bank and Green Street Green Primary School and the streets around them. The nearest railway station is Knockholt station, roughly 0.8 miles east. A little further out are Crofton Roman Villa (2.4 miles north-west) and Lullingstone Castle (3.8 miles east). For a walk, there’s Betsom's Hill and Downe Bank Nature Reserve.
What the job involves on each surface
Brick reveals
Loose mastic comes out and deep gaps are packed before the new mastic goes in.
Tenement and terrace windows
In shared buildings, the windows may be part of a wider repair, so check who is responsible first.
What we’re called out for in Pratt's Bottom
Most of it is simply age. Even well-laid mastic needs renewing in time, depending on exposure and upkeep.
The problems people generally mention when they call are:
- Mastic worn away on windows facing the weather
- Gaps where the frame meets the masonry
- Wind and rain getting in round a sash window
- Crumbling sand mastic round a window
Pratt's Bottom is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book.
Comparing quotes
- How the surfaces are prepared before sealing
- What insurance they hold
- What happens if the job turns out different
- Which colour the sealant will be
What happens on the day
Before we leave, we go over the finished joints with you and explain the cure time. The work normally takes a few hours per window, depending on the condition of the joints, depending on the amount of work. Many London jobs are in flats, so we come ready for stairs, narrow hallways and shared entrances. If the building has a concierge, managing agent or access rules, tell us when you book.
- We check each window surround and the condition of the joint.
- 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.
How to prepare
- Keep pets and children clear of the area while we work
- Clear the area around the work
- Mention any leaks or damp you’ve noticed
Ask for a quote
We don’t publish a price list. Instead, your job gets its own clear quote. To arrange one, call 0345 464 0079 or drop us an email.
Related advice
Why it’s worth doing now in Pratt's Bottom
A silicone bead can be quicker, but it can look wrong on a period surround. Sand mastic is the traditional material and blends with the stone or brick. Damp from a failed joint spreads quietly in older London brickwork and timber, and by the time it shows on a wall or ceiling in Pratt's Bottom, the repair is bigger than the sealant job would have been.
There are no prices on our website, because each job is priced on what it involves. For a quick quote, please phone 0345 464 0079 or send us an email and we’ll talk you through it.
What you get with us
- Domestic, commercial and hotel work
- Any old sealant cut out fully, not covered over
- 20+ years of sealant experience
- An ARBOMaster approved applicator
When something else is needed
A few problems are outside what sealant work can do:
- Crumbling stone or brickwork round the window
- Cracked or broken glass
- Planning or listed building consent (your local planning authority decides)
If in doubt, call 0345 464 0079 or drop us an email and we’ll say what we think.
Joints and surfaces we work on
- Brick reveals
- Period & listed homes
- Tenement windows
- Sash and case windows
- Timber door frames
- Stone surrounds