Greater London · England
Sand Mastic in West Dulwich
Specialist sand mastic for West Dulwich: careful preparation, the right product and tidy work. Ask us for a quick quote.
- Old sand mastic that has cracked, crumbled or fallen out
- Cement or filler used on old window joints that has cracked
- Draughts and rain around sash boxes
Common problems we fix in West Dulwich
Sand mastic slowly weathers. It dries out, cracks and loses its grip on the stone or timber.
The problems people normally mention when they call are:
- Window mastic to renew ahead of painting
- Silicone on a period window that looks wrong
- Open joints round the window box
- Mastic worn away on windows facing the weather
As a London address, West Dulwich can be tricky for parking: tell us about permits, visitor bays or off-street space when you book.
Before booking anyone
- Who does the work, and how experienced they are
- How the surfaces are prepared before sealing
- The length of the guarantee
- Are they insured?
Sand mastic in West Dulwich, done properly
Old sand mastic cracks, crumbles and falls out over time, leaving gaps round the window. We rake it out and renew it and tidies the surround. We work on tenement windows, stone surrounds and sash and case windows, and the jobs we see most are failed mastic on an exposed elevation and crumbling sand mastic round a window.
Much of London’s older housing was built with timber sash windows, some still in place and some long since replaced. Whatever is in the opening now, the joint between frame and wall is what keeps the weather out.
All our work comes with a one-year guarantee, wherever you are in Greater London.
- Where
- West Dulwich (SE21, SE27, SE19)
- Region
- Greater London
- Guarantee
- One year on every job
- Price
- Quoted before any work starts
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
Should I try it myself first?
A careful DIYer can reseal a simple joint, 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.
Different surfaces, different methods
Brick reveals
Loose mastic comes out and deep gaps are packed before the new mastic goes in.
Period and listed homes
Sand mastic is the like-for-like choice for many period homes. If your home is listed, ask your local planning authority about consent.
Honest limits
New sealant can’t fix everything, and we’d rather say so up front. It won’t solve:
- Timber that has rotted
- Sashes that rattle, stick or will not open
- Masonry that needs repairing
If in doubt, ring 0345 464 0079 or send us an email and we’ll say what we think before you book.
Surfaces we seal
- Timber door frames
- Tenement windows
- Brick reveals
- Period & listed homes
- Sash and case windows
- Stone surrounds
How the visit works
Every visit runs the same way: we look at the joints together, mask and protect the surrounding surfaces, do the work and clear up. Most jobs take a few hours per window, depending on the condition of the joints. In West Dulwich, flats, stairs and shared entrances are part of the routine. If the building has a concierge, managing agent or access rules, tell us when you book.
- We start by checking each surround and agreeing the joints to renew.
- Old, loose mastic is raked out and the joint cleaned.
- Deep voids are packed so the mastic is the right thickness.
- The mastic is mixed, pressed into the joint by hand and shaped.
- The mastic is finished to sit tidily against the stone or brick.
Preparing for the visit
- For indoor joints, keep the area dry beforehand if you can
- Keep children and pets away from the work area
- Clear items away from the joints we’re working on
Ask for a quote
For a quote, phone 0345 464 0079 or send us an email with the location and a short description of the problem. You’ll have a clear quote before we start.
Related advice
Keeping the joints in good condition
Good habits help new joints last longer. A few tips:
- Inspect the joints round the windows every year or so
- Get any rot dealt with first
- Clear gutters so water does not pour onto the windows
- Ask us before painting near the mastic
Make sure water drains away from the window surround. Constant wetting wears the mastic faster.
It’s best to renew mastic before painting the windows. Painting over failed mastic hides the problem for a while.
Your questions about sand mastic in West Dulwich
Is parking a problem for a job in West Dulwich?
Parking in West Dulwich, as in most of London, takes a little planning: a visitor permit or a nearby bay makes the day run more smoothly.
Can you help a landlord with a rental near Sydenham Hill station?
Yes, we work for landlords and agents. Just ring 0345 464 0079 or email us and tell us about the property, and we’ll send you a clear quote.
Does someone need to be in?
For indoor joints, yes, someone needs to let us in. After that, you can carry on with your day.
Which is right for my windows, sand mastic or modern sealant?
Sand mastic normally suits period timber windows best. On modern frames, we’d normally use a flexible sealant, and we’ll explain why.
Can you quote for more than one area?
Yes. More than one area can go on one quote.
Do you come to West Dulwich?
Yes. We cover West Dulwich and the rest of Greater London. For a quote, phone 0345 464 0079 or drop us an email.
Do you take out the old sealant first?
Yes. All of the old material is cut out and the joint cleaned.
How do I get a quote for sand mastic in West Dulwich?
We do not publish prices, because the cost depends on the job: how much there is, what’s there now, how we reach it and what it needs. We agree the price before any work begins.
Places near West Dulwich
Other services in West Dulwich
West Dulwich homes and the weather
In London conversions and blocks, the lease decides who is responsible for the frames, so check that before you book. 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 Dulwich Wood Primary School? Then larger buildings have plenty of frames, and the mastic around each one ages. Homes close to Church of St Stephen include some older properties, and the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
West Dulwich is about 1 mile north-east of West Norwood, in Greater London. Homes, rented property, offices and hotels in West Dulwich is covered for sand mastic, old or new, large or small. The work is guaranteed for a year. Our Greater London coverage runs to 764 places, West Dulwich among them.
We cover every part of SE21, SE27 and SE19 for sand mastic and the streets around it. Streets in the area include Berry Lane, Clive Road and Myton Road, all of which we cover. West Dulwich is on the A2199, which makes it straightforward to reach. If you are just outside West Dulwich, we cover Sydenham Hill (1 mile east), West Norwood (1 mile south-west), Gipsy Hill (1 mile south), Dulwich (1 mile north) and Upper Norwood (1 mile south). Further out, we also cover London (5 miles north), City of Westminster (6 miles north-west), Marylebone (6 miles north-west), Kensington (7 miles north-west), St Pancras (7 miles north) and Shoreditch (6 miles north).
What’s near West Dulwich
Around West Dulwich, our work takes us to homes and buildings near The Wood House, Dulwich Prep & Senior and Kingsdale Foundation School and the streets around them. West Dulwich has its own railway station: Sydenham Hill station. A little further out are British Vintage Wireless And Television Museum (under half a mile west) and St Christopher's Hospice (1.3 miles south-east). Green spaces nearby include Battersea Park Lake and Dulwich Upper Wood.
Why it’s worth doing now in West Dulwich
If you are redecorating, renew the mastic first. Painting over failed mastic does not seal it, and the new mastic is traditionally left unpainted. 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.
Instead of a standard rate, we price the job in front of us: how many joints, what’s in them now and how we reach them. You’ll know the price before we begin.
Why us?
- Fully insured
- 4.9 on Google from 180+ five-star reviews
- Over 20 years’ experience
- Neat joints and a tidy finish
Take a look at our cost guide and customer reviews.