Greater London · England
Sand Mastic in Crook Log
Traditional burnt sand mastic around sash and case windows and doors in stone and brick in Crook Log, with a 12-month guarantee on every job. Ask us for a quote.
- Mastic worn away on windows facing the weather
- Cracked mastic round a front door frame
- Tired mastic found when preparing windows for paint
About our sand mastic in Crook Log
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 and built up by hand. On older homes, it suits the building far better than silicone. We work on brick reveals, tenement windows and timber door frames, and the jobs we see most are mastic round period door frames that has failed and tired mastic found when preparing windows for paint.
London has a lot of flats and conversions, where windows are often on upper floors. Who looks after the outside of the frames can depend on the lease, so check that first.
The work is guaranteed for twelve months. If there’s a problem with our work within the year, let us know and we’ll sort it.
- Location
- Crook Log (DA7, DA6, DA16)
- Region
- Greater London
- Guarantee
- 12 months on all our work
- Price
- Quoted before any work starts
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
Signs you need sand mastic in Crook Log
Timber frames move with the seasons. The movement cracks the mastic over time.
If you can see any of these, it’s time to have the joints looked at:
- Gaps round a timber door in stone or brick
- Tired mastic found when preparing windows for paint
- Gaps between timber frames and stone or brick
- Cement or filler used on old window joints that has cracked
If you live in an older home near Trinity Baptist Church, frames set in older brick or stone need a sealant that suits the wall as well as the frame.
What to look for in a quote
- Who turns up on the day
- Whether you can choose the colour
- What the cure time is
- What happens if they find a problem under the old sealant
Crook Log homes and the weather
In London conversions and blocks, the lease decides who is responsible for the frames, so check that before you book. London and the South East are among the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
If you let a flat or house near Bexleyheath station, cracked sand mastic around sash windows lets in the draughts tenants complain about. If you look after a building such as Crook Log Primary School, its window and door frames need their mastic kept sound, just like a home’s.
Crook Log is about 3 miles south-east of Plumstead, in Greater London. Across the DA7 area, our applicators can take on sand mastic. 764 places in Greater London are on our list, large and small. We also work in London, around 10 miles away.
Every address in DA7, DA6 and DA16 is covered for sand mastic, from the main roads to the quietest streets. If you need sand mastic at a property on Bean Road, Lion Road and Alers Road or a nearby road, our applicators can take on the job. If you are just outside Crook Log, we cover Upton (1 mile east), Bexleyheath (1 mile east), Welling (1 mile west), Blendon (1 mile south) and Bexley (1 mile south). Within a short drive, we also cover London (10 miles west), City of Westminster (13 miles west), Marylebone (12 miles west), Kensington (14 miles west), St Pancras (11 miles north-west) and Shoreditch (10 miles north-west).
Near you in Crook Log
Locally, jobs take us to homes and businesses close to Danson Park, St Columba's Catholic Boys' School and The Crook Log Public House. Crook Log has its own railway station: Bexleyheath station. Nearby you will also find Bexley Museum (1.7 miles south-east) and Broadway Shopping Centre (0.9 miles east). Not far away are Summer Hill and Wansunt Pit.
How we quote for sand mastic
The quote reflects the job in front of us. We take into account:
- The old material and how stubborn it is
- When we can work, for business premises
- Access and height
- The number and length of the joints
The cost reflects the work involved, not guesswork. That’s why we ask about the job first and agree the price before starting.
Helping us quote
The more you tell us, the more accurate the quote. When you get in contact, it helps to mention:
- Any access issues, like height or stairs
- Whether it has been sealed before
- What’s wrong with the joints now
- Whether it’s a home or a business
Quotes start with a quick conversation. Describe the problem, the location and the size of the job. Whenever you are ready, phone 0345 464 0079 or email us.
How the job changes by surface
Period and listed homes
Many older homes were built with sand mastic round the windows. On listed buildings, check with your planning authority first.
Tenement and terrace windows
Windows above ground floor need the right access. Let us know the floor and we’ll confirm access.
Nearby places to Crook Log
What else we do in Crook Log
Why deal with it now?
If you’re redecorating, renew the mastic first. Paint over cracked mastic will not stop the gaps and traditional guidance is to leave the new mastic unpainted. Damp from a failed joint spreads quietly in older London brickwork and timber, and once it shows in Crook Log, the repair is bigger than a sealant job.
There are no prices on our website, because each job is priced on what it involves. For a quick quote, please ring 0345 464 0079 or drop us an email.
Why Crook Log customers choose us
- We are fully insured
- Old sealant always removed completely
- Tidy, careful work
- 180+ five-star Google reviews
DIY sealant or a professional job?
The difference is mostly in the preparation and the product. Joints are cleaned back to sound surfaces and dried, and the sealant is chosen for how the joint moves and where it is, and the work is guaranteed for a year.
Too much sealant is as bad as too little. A thick, smeared bead looks untidy and does not move well, and the joint depth matters as much as the finish.
How the visit works
Once we’re on site, we check the joints match what you told us. If anything is different, we explain it before carrying on. After that, the work takes a few hours for a single window, longer for several. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in Crook Log. A visitor permit or a nearby bay makes the visit run more smoothly.
- First, we look at the surrounds with you and agree what needs doing.
- The loose and crumbling mastic is raked out and the joint cleaned.
- Large voids are packed out first, so the mastic is not too thick.
- Sand mastic is mixed and applied by hand, then shaped to the joint.
- The finish is dressed so it sits neatly against the stone or brick.
Preparing for the visit
- Tell us about any water getting in
- Clear items away from the joints we are working on
- Tell us about access, such as stairs, a lift or high-level joints
Ask for a quote
For sand mastic in Crook Log, call 0345 464 0079 or drop us an email. Tell us what the problem is and where, and you’ll get a clear quote before any work starts.
Read more
How to look after the new joints
Aftercare is simple:
- Keep sills and gutters clear so water drains away
- Get any rot dealt with first
- Go gently near the mastic when preparing windows
- Plan mastic work ahead of painting
Do not run silicone over the new mastic. If you see a crack, ask us to take a look before trying a quick fix.
Crumbling mastic lets rain into the joint. That water can reach the timber frame and the wall, so renewing it early is worth it.
Crook Log questions
Do you cover Crook Log for sand mastic?
Yes. Our work covers London and the South East, and Crook Log is part of that. You can ring 0345 464 0079 or send us an email and let us know what needs doing, and we will give you a clear price.
Is parking an issue for sand mastic in Crook Log?
Parking in Crook Log, as in most of London, takes a little planning: a visitor permit or a nearby bay makes the day run more smoothly, so mention what’s available when you book.
Is consent needed for window work on a listed home?
It’s best to ask your local planning authority first. Like-for-like sand mastic is often the preferred finish but the decision is theirs.
Do you guarantee sand mastic work?
All our work has a one-year guarantee, and we’re fully insured.
How long does sand mastic take to harden?
It skins over fairly quickly but takes longer to harden fully. We will explain what to expect before we leave.
Can you do several jobs on one visit?
Of course. Doing several areas at once is usually more efficient, so mention them when you ask for a quote.
Can sand mastic be painted?
The usual advice is to leave sand mastic unpainted. If you are redecorating the window, ask us first and we will talk you through it.
Can new sealant go over the old?
No, it won’t last. It can look neat for a few weeks, but the new bead soon lifts. Removing the old sealant completely is the only lasting way.