Greater London · England
Sidcup Sand Mastic
Professional sand mastic in and around Sidcup, with every bit of old sealant taken out first and a 12-month guarantee.
- Cement or filler used on old window joints that has cracked
- Draughts and rain around sash boxes
- Modern sealant on a period surround
DIY sealant or a professional job?
Some sealant jobs are within reach of a careful DIYer, such as a straightforward joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
Not every job suits DIY: work at height, external movement joints, fire-rated sealant and large areas need the right product, the right access and the right method.
Sand mastic in Sidcup
Sand mastic is the traditional way to point the gap between a timber window frame and the stone or brick around it. It’s a mix of sand and a linseed-oil-based binder, applied by hand. On older homes, it suits the building far better than silicone. If you have draughts and rain around sash boxes and mastic dropping out of the joint, we can help.
London homes have every kind of window, from timber sashes in period terraces to aluminium and uPVC in newer blocks. The mastic around them dries out and cracks with age, which is when draughts and damp patches appear in homes in Sidcup.
The work is guaranteed for twelve months. If something isn’t right with it in that time, tell us and we’ll put it right.
- Where
- Sidcup (DA14, DA15, SE9, DA5)
- Wider area
- Greater London
- Cover
- A year, on every job
- Quote
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
For landlords and businesses
Businesses can book us for washrooms, kitchens, offices and more. On commercial sites, working times can be discussed when we quote.
Mouldy or split sealant often shows up at the end of a tenancy. We can quote for more than one property at once.
Why it’s worth doing now in Sidcup
Replacing sash windows is a big decision for a period home, and in listed buildings it may need consent. Where the frames are in good order, new mastic seals the surround. In London conversions, one flat’s bathroom is often above another flat’s ceiling, and a slow leak from a failed seal can end up in the flat below. Putting it right early is much less trouble.
No two jobs are quite the same, so we quote each one individually. Size, access and the product the joint needs all make a difference, and we’ll explain the quote if you ask.
Why Sidcup clients choose us
- We leave the area clean and tidy
- Quality sealants from Arbo and Everbuild
- Any old sealant cut out fully, not covered over
- Anti-fungal sanitary silicone in wet areas
Read how sealant jobs are priced and our reviews.
Frames and glazing around Sidcup
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 Danson House (about 1.7 miles north) nearby, there’s older building stock in the area around Sidcup as well as newer homes. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that is traditional sand mastic.
Letting a property close to Sidcup station? Then cracked sand mastic around sash windows lets in the draughts tenants complain about. If you live in an older home near Holy Trinity Church, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Sidcup is about 3 miles north of Orpington, in Greater London. Wherever you are in the DA14 postcode area, we cover sand mastic for homes and businesses. We cover 764 towns and villages across Greater London, large and small. For nearby work, see our London page.
Here we cover the DA14, DA15, SE9 and DA5 postcode area for sand mastic. That includes homes and businesses on Station Road, High Street and Jubilee Way. You will find Sidcup on the A211 and A2001, which makes it straightforward to reach with everything needed for sand mastic. Other places close to Sidcup include Albany Park (1 mile south), Blendon (1 mile north-east), Foots Cray (1 mile south-east), Bexley (2 miles north-east) and North Cray (2 miles east). We also work in nearby towns such as London (10 miles north-west), City of Westminster (12 miles north-west), Marylebone (12 miles north-west), Kensington (14 miles west), St Pancras (11 miles north-west) and Shoreditch (10 miles north-west).
Near you in Sidcup
Around Sidcup, our work takes us to homes and buildings near The Alma pub, Waring Park and Chislehurst and Sidcup Grammar School and the streets around them. There’s a railway station in Sidcup itself: Sidcup station. A little further out are Queen Mary's Hospital (1 mile south) and Broadway Shopping Centre (2.4 miles north-east). Green spaces nearby include Summer Hill and The Tarn.
Common questions in Sidcup
Is parking a problem for a job in Sidcup?
It can be, so it helps to tell us about permits, visitor bays or off-street space when you book. The visit is then planned around what’s available.
Can you do sand mastic in Sidcup?
Yes, Sidcup is within the area we cover. We work across London and the South East. You can call 0345 464 0079 or drop us an email and tell us what needs doing, and we will give you a clear price.
Is the work guaranteed?
All our work has a one-year guarantee, and we are fully insured.
Which products do you use?
The product depends on the job: anti-fungal sanitary silicone in wet areas, and other sealants where joints move or face the weather. Brands we use include Arbo and Everbuild.
Is there any odour?
Possibly a little. Any smell clears as the sealant cures.
What do you need from me for a quote?
Only a few details: where it is, what you’ve noticed and how we reach it. Then phone 0345 464 0079 or email us.
How much does sand mastic cost in Sidcup?
Every job is different, so each one gets its own quote. For a quick quote, call 0345 464 0079 or send us an email with a short description of the job.
Can landlords and businesses book you?
Yes. As well as homeowners, we work for landlords, agents, businesses and hotels across Greater London.
Common problems we fix in Sidcup
Paint, silicone or cement used over old mastic causes problems. They don’t suit the joint, and they normally need raking out.
The problems people generally mention when they call are:
- Old cement repairs round a window that have failed
- Mastic round period door frames that has failed
- Draughts and rain around sash boxes
- Gaps between timber frames and stone or brick
Sidcup is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book.
Questions to ask before you book
- How long the guarantee is
- How long to leave it before use
- How the colour is chosen
- Whether all the old sealant comes out first
Also near Sidcup
What else we do in Sidcup
The process
When we arrive, we start by going over the job with you, so there are no surprises. Surfaces next to the work are protected before any work begins. The work generally takes a few hours per window, depending on the condition of the joints. For a job in Sidcup, 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.
- We look at the surrounds with you and agree the joints to renew.
- Old mastic and any loose material are raked out.
- We pack any deep voids first.
- We apply the mastic by hand and shape it.
- The surface is finished to suit the stone or brick.
Before we arrive
- For indoor joints, keep the area dry beforehand if you can
- Plan for the work area to be out of bounds to pets and children
- Clear items away from the joints we are working on
Getting a quote
If you are in Sidcup and need sand mastic, call 0345 464 0079 or drop 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.
Advice
What we can’t put right
In fairness, there are a few things sealant will not fix:
- Crumbling stone or brickwork round the window
- Planning or listed building consent (your local planning authority decides)
- Sash cords, weights and draught-proofing of the sashes
If you are not sure, just ring 0345 464 0079 or email us and we’ll give you a straight answer.
What we seal
- Brick reveals
- Period & listed homes
- Tenement windows
- Timber door frames
- Sash and case windows
- Stone surrounds
What affects the cost of sand mastic
For a quick quote, just ask. The main things that affect it are:
- The product the joint needs
- Access and height
- Whether there’s mould to deal with
- How much old sealant there is and how hard it is to remove
Combining jobs into one visit normally makes better use of the time than several visits, so tell us about everything that needs sealing. You will get one clear quote for the whole job.
What to tell us for a quote
Photos by email are helpful but not essential. Try to tell us:
- Pictures of the joints, sent by email
- The rough size of the job
- The type of property
- The problem you’ve noticed
Need a quote? Please phone 0345 464 0079 or drop us an email and tell us about the job. You will know what we plan to do, and what it will cost, before any work begins.