Oxfordshire · England
Sand mastic for sash & case windows in Forest Hill, Oxfordshire
We cover Forest Hill for traditional burnt sand mastic around sash and case windows and doors in stone and brick. Old material cut out, joints cleaned and sealed neatly and a one-year guarantee.
- Old sand mastic that has cracked, crumbled or fallen out
- Wind and rain getting in round a sash window
- Cement or filler used on old window joints that has cracked
Leave it or put it right?
Filling over old, loose mastic does not last. We remove the loose material first so the new work lasts. Where a wall is exposed, as many are in small places like Forest Hill, wind-driven rain gets into any failed joint, and older walls, once damp, take a long time to dry.
What it costs depends on the size of the job, how much old material has to come out and access to the work. We give a clear quote before we start, so you know where you stand.
What you get with us
- Approved under the ARBOMaster scheme
- We are fully insured
- Domestic, commercial and hotel work
- Old sealant always removed completely
About our sand mastic in Forest Hill
Sand mastic doesn’t last for ever, leaving gaps round the window. We rake it out and renew it and tidies the surround. Common call-outs are for old sand mastic that has cracked, crumbled or fallen out and old cement repairs round a window that have failed, on tenement windows, timber door frames and sash and case windows.
Somewhere as small as Forest Hill, older homes often have timber frames set in stone or brickwork. Not every older frame suits a modern silicone bead, and sometimes a traditional sand mastic is the better choice.
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
- Forest Hill (OX33)
- Region
- Oxfordshire
- Guarantee
- 12 months on all our work
- Quotes
- A clear quote up front
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
What the job involves on each surface
Sash and case windows
The mastic round a sash window is on show so we finish it carefully.
Timber door frames
Door frames get knocked and soaked and the mastic can crack early. We rake it out and renew it.
How to look after the new joints
Looking after new joints is easy:
- Inspect the joints round the windows every year or so
- Do not paint over the new mastic
- Avoid patching sand mastic with silicone
- Keep sills and gutters clear so water drains away
Don’t run silicone over the new mastic. If you see a crack, ask us to take a look rather than patching it.
Small cracks are a sign the mastic is ageing. It’s easier to renew it before it drops out.
DIY sealant or a professional job?
If you do try it yourself, take your time over the preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it doesn’t work out, we can still put it right.
Sealing over old silicone is the commonest DIY error. New silicone will not bond to old, so it peels away and traps moisture behind it. All the old material has to come out first.
What happens on the day
There is not much for you to do on the day. Show us the job and we will take it from there. The job generally takes a few hours for a single window, longer for several from start to finish. For a village or hamlet like Forest Hill, 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.
- Each surround is checked first.
- The joint is raked out and cleaned.
- Large voids are packed out.
- We point the joint with sand mastic by hand.
- We finish the mastic to a tidy line.
Getting ready for the visit
- Mention any sign-in or site rules at work premises
- Keep children and pets away from the work area
- Mention any tricky access
How to get a quote
Need a quote? Please phone 0345 464 0079 or email us with a few details. We’ll explain what we’d do and give you a clear quote before any work starts.
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Questions from Forest Hill
Is Forest Hill in your area for sand mastic?
Yes, Forest Hill is within the area we cover. We work across London and the South East. You can phone 0345 464 0079 or email us and let us know what needs doing, and we will give you a clear quote.
Will you come out to Forest Hill?
Yes, Forest Hill is covered. We work across London and the South East, from towns to the smallest places. The journey is planned ahead, so it helps to know about access.
How long does sand mastic take?
Most jobs take anything from a few hours to a full day, depending on how many windows. We will confirm how long when we quote.
Which products do you use?
Quality sealants from brands including Arbo and Everbuild, picked for each joint. We will tell you what we are using and why.
Which is right for my windows, sand mastic or modern sealant?
We will talk it through with you. Sand mastic suits many period homes, and modern sealants suit newer frames.
Is consent needed for window work on a listed home?
Check with your local planning authority. They’ll tell you if consent is needed.
Do you have insurance?
Yes. Mr Mastic is fully insured, with over 20 years’ experience in sealant work.
Will it make a mess?
Tidy work is part of the job. We protect what’s around the joints.
Nearby places to Forest Hill
Also in Forest Hill
Windows and doors in Forest Hill
Compared with the north and west, the South East gets less rain, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. Historic houses like Garsington Manor (about 3.6 miles south) are a reminder that the area around Forest Hill 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.
If you live in an older home near Church of St Nicholas, frames set in older brick or stone need a sealant that suits the wall as well as the frame. For site and facilities teams at buildings such as Sandhills Community Primary School, larger buildings have plenty of frames, and the mastic around each one ages.
Forest Hill is about 3 miles east of Oxford, in Oxfordshire. Across the OX33 area, we cover sand mastic for homes and businesses. We cover 443 towns and villages across Oxfordshire, large and small.
We cover every part of OX33 for sand mastic and the streets around it. Whether your property is on Main Street, Milton Crescent and Powell Close or a nearby road, we can help. Neighbouring places we cover for sand mastic include Holton (1 mile south-east), Stanton St John (1 mile north), Littleworth (1 mile south), Risinghurst (2 miles west) and Wheatley (2 miles south-east). Further out, we also cover Oxford (3 miles west), Didcot (11 miles south), Bicester (9 miles north), Abingdon-on-Thames (8 miles south-west), Witney (14 miles west) and Thame (8 miles east).
Landmarks near Forest Hill
In Forest Hill, that means homes and buildings near Shotover Country Park, The Kings Arm's Public House and Wheatley Park School, among other places. Other landmarks nearby include Waterperry Gardens Rural Museum (2.9 miles east) and Templars Square (3.5 miles south-west). Not far away are CS Lewis Nature Reserve and Shotover.
Work for landlords, hotels and businesses
Whether it’s one flat or a portfolio, you get the same standard of work: the old material taken out, careful preparation and a 12-month guarantee.
Housing providers, facilities teams and property managers book us too in Forest Hill and across Oxfordshire. Several sites can be quoted together, and we’re fully insured for the work.
How we quote for sand mastic
We quote each job individually. This is what makes a difference:
- Any working-time requirements on site
- The product the joint needs
- The size of the job
- Any mould that needs treating
A few things move the cost up or down: the old material and how easily it comes out, whether mould needs treating, and whether we need extra access for height. Your quote takes all of that into account.
What we need to know
Before you ask for a quote, have a think about:
- Pictures of the joints, sent by email
- What’s wrong with the joints now
- Access, such as stairs, a lift or height
- If someone has resealed it before
A good description makes for an accurate quote. Tell us where the job is, what’s wrong and how much there is, and add photos by email if you can.