Buckinghamshire · England
Downley Sand Mastic
Traditional burnt sand mastic around sash and case windows and doors in stone and brick for householders, landlords and businesses in Downley. Fully insured, ARBOMaster approved and guaranteed for a year.
- Gaps round a timber door in stone or brick
- Weathered mastic on the most exposed windows
- Window mastic to renew ahead of painting
How it works
At the end, we look at the finished work together and tell you how long to leave it. The visit itself normally takes a few hours for a single window, longer for several, depending on the size of the job. Somewhere as small as Downley, access is often the only tricky part. If the job is outside, mention outbuildings, exposed walls and how to reach them.
- First we agree which joints need doing.
- Old mastic and any loose material are raked out.
- Deep gaps are packed so the mastic sits at the right depth.
- The sand mastic is mixed and pressed into the joint by hand.
- The surface is finished to suit the stone or brick.
Getting ready for the visit
- On commercial sites, let us know about site rules
- Mention any leaks or damp you’ve noticed
- Move anything stored near the joints
Getting a quote
Call for a quick quote, or send an email if you’d rather. Describe what needs sealing and we’ll explain what’s involved before giving you a price.
Advice
Sand mastic for homes and businesses in Downley
Sand mastic skins over fairly quickly but full hardening takes longer. Traditionally, sand mastic is left unpainted, so ask us before you decorate. We are often asked to deal with wind and rain getting in round a sash window and gaps between timber frames and stone or brick, on brick reveals, period & listed homes and sash and case windows.
Mastic can only go onto a dry, clean joint, so window work in Downley is booked around the forecast. Let us know about access to all the frames, upstairs ones included.
We stand behind the work with a 12-month guarantee, so you’re covered after we have gone.
- Place
- Downley (HP13)
- Region
- Buckinghamshire
- Cover
- 12 months on all our work
- Price
- A clear quote up front
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
Nearby places to Downley
Also in Downley
Downley: your questions answered
Do you cover smaller places like Downley?
Yes, we do. Our work covers London and the South East, and smaller places are part of that. The journey is planned ahead, so it helps to know about access.
I let a flat near High Wycombe station. Can you help?
Yes, we work for landlords and agents. Just phone 0345 464 0079 or email us and tell us about the property, and we will give you a clear price.
When will the new mastic be hard?
It forms a skin fairly soon, then hardens over a longer period. Timing depends on the weather and the joint.
Do you offer different sealant colours?
We will suggest a colour to suit the surroundings, from white and clear to greys and other shades. The product needed can limit the range.
How long does the job take?
Most jobs take a few hours for a single window, longer for several, including the preparation. Your quote will say how long we expect yours to take.
Can old silicone round a sash window be swapped for sand mastic?
Yes, we do this often. The old silicone has to come out completely so the mastic beds in well.
What exactly is sand mastic?
Sand mastic is a traditional material for pointing round windows and doors. It’s made with sand and a linseed-oil-based binder.
Can new sealant go over the old?
No. Fresh sealant doesn’t stick to old sealant, and anything trapped underneath, including mould and water, stays there. It all has to come out first.
What affects the cost of sand mastic
Your quote is based on your job. We take into account:
- Which sealant suits the joint
- Mould in or behind the old joints
- How many rooms, windows or areas are involved
- The old material and how stubborn it is
Combining jobs into one visit is normally more efficient than separate visits. You will get one clear quote for the whole job.
Asking for a quote
Photos by email are helpful but not essential. Please mention:
- What the problem is, such as mould, gaps, leaks or cracking
- The rough size of the job
- The address or postcode of the job
- The type of property
Getting a quote is simple: let us know what needs doing and where. Photos by email help us understand the job.
Sand mastic in Downley: local notes
Historic houses like Hughenden Manor (about 0.8 miles east) are a reminder that the area around Downley has older buildings as well as new. Where a home is older, older timber frames in brick or stone need a different approach from a modern uPVC window. Compared with the north and west, the South East gets less rain, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
Letting a property close to High Wycombe station? Then cracked sand mastic around sash windows lets in the draughts tenants complain about. Homes close to St. James the Great include some older properties, and frames set in older brick or stone need a sealant that suits the wall as well as the frame.
Downley is about 2 miles north-west of High Wycombe, in Buckinghamshire. Homes, rented property, offices and hotels in Downley can book us for sand mastic, old or new, large or small. Every job comes with our one-year guarantee. Our area takes in 263 places across Buckinghamshire, large and small. You can also see our page for Reading, about 16 miles away.
Postcode districts we cover here for sand mastic: HP13. We cover properties on Willoughby's Walk, Gray's Lane and West Court and the roads around them. If you are just outside Downley, we cover Naphill (1 mile north), Hughenden Valley (2 miles north-east), High Wycombe (2 miles south-east), Terriers (2 miles east) and Four Ashes (2 miles east). Larger places within reach include Aylesbury (12 miles north), Chesham (8 miles north-east), Marlow (5 miles south), Amersham (8 miles east), Beaconsfield (6 miles south-east) and Chalfont St Peter (10 miles east).
Landmarks near Downley
Typical jobs here are in homes near The Royal Grammar School, Le De Spencers Arms and The Tower, among other places. The nearest railway station is High Wycombe station, roughly 1.8 miles south-east of the centre. A little further out are High Wycombe Castle (1.6 miles south-east) and Eden (1.5 miles south-east). Open spaces near Downley include Prestwood Local Nature Reserve.
What we cannot put right
Honest advice matters more to us than a booking, so here’s what sealant can’t fix:
- Sashes that rattle, stick or won’t open
- Putty and glazing repairs
- Crumbling stone or brickwork round the window
If you’re not sure, just phone 0345 464 0079 or drop us an email and we’ll give you a straight answer.
What we seal
- Stone surrounds
- Period & listed homes
- Sash and case windows
- Tenement windows
- Brick reveals
- Timber door frames
Signs you need sand mastic in Downley
Age is the main cause. Even well-laid mastic needs renewing in time, depending on exposure and upkeep.
If you can see any of these, it’s time to have the joints looked at:
- Weathered mastic on the most exposed windows
- Modern sealant on a period surround
- Tired mastic found when preparing windows for paint
- Gaps between timber frames and stone or brick
If you look after a building such as The Downley School, the mastic around its windows and doors needs looking after like any other building’s.
Before booking anyone
- What preparation is included
- What guarantee comes with the work
- How long to leave it before use
- Who does the work, and how experienced they are
For landlords and businesses
Housing providers, facilities teams and property managers book us too. Several sites can be quoted together.
We regularly work with letting and managing agents. Send the address, what’s needed and the access arrangements.
Can I do it myself?
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas need the right product, the right access and the right method.
Sealing over old silicone is the commonest DIY error. Silicone doesn’t stick to old silicone, so it lifts and traps water and mould underneath. All the old material has to come out first.
Why act early in Downley
An open joint round the frame lets weather in. Left, water can reach the timber and the wall, so dealing with it now protects both. Older cottages and farmhouses around Downley can have timber floors and frames, and water through a failed joint can rot timber if it’s left.
What it costs depends on the size of the job, how hard the old material is to remove and access to the work. You’ll have a clear quote before any work starts, so you know where you stand.
Why book with us
- Trusted Arbo and Everbuild sealants
- 4.9 on Google from 180+ five-star reviews
- Neat joints and a tidy finish
- An ARBOMaster approved applicator
Read how sealant jobs are priced and customer reviews.