Surrey · England
Downside Sand Mastic
Traditional burnt sand mastic around sash and case windows and doors in stone and brick in Downside, with a 12-month guarantee on every job. Ask us for a quote.
- Open joints round the window box
- Tired mastic found when preparing windows for paint
- Crumbling sand mastic round a window
Sand mastic in Downside
Traditional burnt sand mastic blends with stone and brick surrounds. It’s a good fit for period properties, where modern sealant can look out of place. We work on timber door frames, sash and case windows and period & listed homes, and the jobs we see most are gaps where the frame meets the masonry and window mastic to renew ahead of painting.
Mastic can only go onto a dry, clean joint, so window work in Downside is booked around the forecast. Let us know about access to all the frames, upstairs ones included.
We stand behind the work with a one-year guarantee, so you’re not left on your own once the job is done.
- Place
- Downside (KT11)
- Wider area
- Surrey
- Cover
- 12 months on all our work
- Price
- A clear price before work begins
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
DIY sealant or a professional job?
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.
If you are set on DIY, put the effort into preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it fails, we can still redo it.
How we quote for sand mastic
Every job gets its own quote. These are the things that affect it:
- How easy the joints are to reach
- Whether old sealant or filler has to be cut out
- How much there is to do
- Whether there’s mould to deal with
We don’t show prices on the website, because the cost depends so much on the job itself. Call for a quick quote.
What to tell us for a quote
There’s no need for technical detail. Just tell us:
- Whether it has been sealed before
- If it’s domestic, commercial or a hotel
- The rough size of the job
- A few photos by email, if you can
To get a quote, phone 0345 464 0079 or send us an email with the location and a short description of the problem. We’ll send you a clear quote before any work starts.
Towns and villages near Downside
Also in Downside
Surface by surface
Brick reveals
Brick reveals round timber windows are often pointed with sand mastic. It suits older brickwork.
Tenement and terrace windows
Upper-floor windows need access planning. Let us know the floor and we’ll confirm access.
Common questions in Downside
Can you do sand mastic in Downside?
Yes, Downside is within the area we cover. We work across London and the South East. You can phone 0345 464 0079 or drop us an email and let us know what needs doing, and we will send you a clear quote.
I let a flat near Cobham & Stoke Dabernon station. Can you help?
Yes, we work for letting agents and landlords. You can call 0345 464 0079 or email us with the address and a few details, and we’ll give you a fixed price before any work starts.
Which products do you use?
It depends on the joint: anti-fungal sanitary silicone in wet areas, and other sealants where joints move or face the weather. Brands we use include Arbo and Everbuild.
Should I check with the council before work on a listed or conservation-area home?
It’s best to ask your local planning authority first. Sand mastic is often favoured as like for like, but they decide.
When will the new mastic be hard?
It forms a skin fairly soon, then hardens over a longer period. The weather and joint depth both affect it.
Can I paint the new mastic?
It’s traditionally left unpainted, which is what traditional guidance recommends. Talk to us before any painting near it.
Do the sealants smell?
That depends on the sealant. Some products have a noticeable smell, others very little, and any smell fades as they cure.
What do you need from me for a quote?
Only a few details: the address or postcode, what’s wrong and any access issues. After that, simply call 0345 464 0079 or drop us an email.
Frames and glazing around Downside
The South East is one of the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day. Historic houses like Byfleet Manor (about 2.7 miles north-west) are a reminder that the area around Downside has older buildings as well as new. Where a home is older, older frames set in brick or stone need a sealant that suits them, and sometimes that’s traditional sand mastic.
In the older streets around St Michael's Chapel, the joint between an old wall and a newer frame is normally the first place rain gets in. Letting a property close to Cobham & Stoke Dabernon station? Then cracked sand mastic around sash windows lets in the draughts tenants complain about. If you look after a building such as St Matthew's CofE Aided Infant School, the mastic around its windows and doors needs looking after like any other building’s.
Downside is about 4 miles west of Leatherhead, in Surrey. From the centre of Downside to the outskirts, we cover sand mastic for every kind of property, from flats and houses to offices and hotels. We cover 395 towns and villages across Surrey, from the larger towns to small villages. There’s also a page for Crawley, about 17 miles away.
Jobs for sand mastic in KT11 is quoted and booked the same way as anywhere else. That includes homes and businesses on Downside Common, Downsview Close and Deacon Close and the roads around them. Close by, we work in Hatchford (1 mile west), Martyr's Green (1 mile south-west), Hatchford End (2 miles west), Whiteley Village (3 miles north) and Wisley (3 miles west). We also work in nearby towns such as Guildford (8 miles south-west), Woking (7 miles west), Camberley (14 miles west), Epsom (6 miles east), Horley (14 miles south-east) and Redhill (12 miles south-east).
Near you in Downside
Around Downside, our work takes us to homes and buildings near The Plough Public House and Parkside School. The closest station to Downside is Cobham & Stoke Dabernon station, about 1 mile north-east of the centre. Other landmarks nearby include Epsom Cottage Hospital (5.1 miles north-east) and Send and Ripley History Society Museum (3.8 miles west). The countryside around Downside includes Jubilee Wood and Boldermere Lake.
When something else is needed
We’d rather tell you now than do work that will not last, so here’s what sealant cannot put right:
- Damaged stone surrounds
- Decisions on consent for listed homes
- Sashes that rattle, stick or will not open
If in doubt, ring 0345 464 0079 or drop us an email and we’ll say what we think before you book.
What we seal
- Period & listed homes
- Tenement windows
- Timber door frames
- Brick reveals
- Stone surrounds
- Sash and case windows
Why act early in Downside
A silicone bead can be quicker, but on period stone or brick it often looks out of place. Sand mastic is the traditional material and finishes neatly against the masonry. In a small place like Downside, homes can be exposed to wind and rain, which finds any gap, and damp in older walls is slow to dry out.
Leaving a failed joint usually makes the job bigger, not smaller, because water and mould keep working on it. If you’re unsure, phone 0345 464 0079 or drop us an email for an honest opinion and a quote.
Why Downside clients choose us
- Fully insured
- Every job guaranteed for a year
- 180+ five-star Google reviews
- Quality sealants from Arbo and Everbuild
Take a look at how sealant jobs are priced and our reviews.
What we do, step by step
On the day, we start by going over the job with you. Surfaces next to the work are protected before work begins. Most jobs take a few hours per window, depending on the condition of the joints. For a village or hamlet like Downside, the journey is planned in advance: let us know about lanes, gates and parking. We bring what the job needs, so it can be finished in one trip where possible.
- We start by checking each surround and agreeing the joints to renew.
- The loose and crumbling mastic is raked out and the joint cleaned.
- Large voids are packed out first, so the mastic isn’t too thick.
- We mix the sand mastic and apply it by hand, shaping it to the joint.
- We dress the surface so it sits neatly against the masonry.
Getting ready for the visit
- Tell us about any previous sealing or DIY attempts
- Mention any sign-in or site rules at work premises
- Where the joints are inside, avoid wetting them before we arrive
Ask for a quote
Call for a quick quote, or send an email if you’d rather. Describe what needs sealing and we will explain what’s involved and send you a clear quote.
Read more
For landlords and businesses
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.
Letting agents often deal with us directly. Send the address, what’s needed and the access arrangements.