Oxfordshire · England
New Marston Sand Mastic
Traditional burnt sand mastic around sash and case windows and doors in stone and brick for householders, landlords and businesses in New Marston. Fully insured, ARBOMaster approved and guaranteed for a year.
- Cement or filler used on old window joints that has cracked
- Crumbling sand mastic round a window
- Tired mastic found when preparing windows for paint
What happens on the day
When we get to you, we check the joints match what you told us. If anything is different, we explain it before carrying on. After that, the work takes anything from a few hours to a full day, depending on how many windows. A visit to New Marston is planned like any other: the time, the access and where to park are agreed in advance. Outdoor jobs depend on a dry day, since sealant needs a dry surface.
- We check each window surround and the condition of the joint.
- We rake out the old mastic and clean the joint.
- Large voids are packed out.
- New sand mastic is applied and shaped by hand.
- We finish the mastic to a tidy line.
Preparing for the visit
- Mention any tricky access
- Mention if the joints have been sealed before
- Move anything stored near the joints
Get a quote
Need a quote? Please phone 0345 464 0079 or email us and tell us about the job. You will know what we plan to do, and what it will cost, before any work begins.
Advice
Sand mastic in New Marston, done properly
Sand mastic skins over fairly quickly but full hardening takes longer. Traditional guidance is not to paint over it and we will advise if you’re redecorating. We are often asked to deal with crumbling sand mastic round a window and tired mastic found when preparing windows for paint, across sash and case windows, period & listed homes and brick reveals.
Homes around New Marston range from older properties to newer houses, and their windows range just as widely. The right sealant depends on the frame and on what it sits in.
All of our work is guaranteed for twelve months, and the guarantee is the same wherever you are.
- Place
- New Marston (OX3, OX1, OX4)
- Wider area
- Oxfordshire
- Guarantee
- A year, on every job
- Quotes
- Quoted before any work starts
- Call
- 0345 464 0079
- Updated
- 26 October 2026
New Marston: your questions answered
I let a flat near Oxford station. Can you help?
Yes, landlords and agents are among the people we work for, and several properties can be quoted together. You can phone 0345 464 0079 or send us an email with the details for a clear quote.
Is New Marston within the area you cover?
Yes. New Marston is within the area we cover, which takes in towns, villages and rural addresses. Our work covers London and the South East. Just mention lanes, gates or anything else about the route when you book.
Where are you based?
Our base is in Crawley, and we work across South East England, London and Scotland.
Will it make a mess?
Tidy work is part of the job. We protect what’s around the joints, and we clear up when we’re done.
Is it worth trying it myself?
Sometimes. The key is preparation: remove all the old material and work on a clean, dry joint. We can always put it right if it fails.
Can you match the sealant colour?
Yes. Sealants come in white, clear, grey and other colours for many products, and we agree the colour with you before work begins.
How much does sand mastic cost in New Marston?
We don’t publish prices, because the cost depends on the job: its size, the old material, access and the product needed. You will get a clear quote before work begins.
What do you put in the joint?
Each joint gets the product that suits it. Movement, water and weather all affect the choice, and we will explain our choice.
Aftercare tips
No joint lasts for ever, but care makes a real difference. A few tips:
- Check with your local planning authority if your home is listed
- Take care around the mastic when scraping paint
- Don’t paint over the new mastic
- Keep sills and gutters clear so water drains away
Make sure water drains away from the window surround. Water sitting against the mastic shortens its life.
Small cracks are a sign the mastic is ageing. It’s easier to renew it before it drops out.
Landlords, agents and businesses in New Marston
We also work for property managers and facilities teams. We can quote a run of properties together, and we are fully insured for the work.
Mouldy or split sealant often shows up at the end of a tenancy, and it’s easy to sort out between tenants. Several properties can go on one quote.
Frames and glazing around New Marston
The South East is one of the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. Historic houses like Holywell Manor (about 0.7 miles south-west) are a reminder that the area around New Marston 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.
Homes close to Saint Michael and All Angels include some older properties, and replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint. Managing a site like St Michael's CofE Primary School? Then its window and door frames need their mastic kept sound, just like a home’s.
New Marston is about 1 mile north of Oxford, in Oxfordshire. If you need sand mastic in New Marston, please call 0345 464 0079 or send us an email for a quick quote. We cover Oxfordshire from our Crawley base, New Marston included. New Marston is one of 443 places in Oxfordshire we cover.
Our applicators cover all of the OX3, OX1 and OX4 postcode area for sand mastic. Sand mastic is available to properties on Ferry Road, Croft Road and Copse Lane and the roads around them. Neighbouring places we cover for sand mastic include Headington Hill (1 mile south-east), Northway (1 mile north-east), Oxford (1 mile south), St Clement's (1 mile south) and Norham Manor (1 mile west). Within a short drive, we also cover Didcot (11 miles south), Bicester (10 miles north), Abingdon-on-Thames (6 miles south), Witney (11 miles west), Carterton (15 miles west) and Thame (11 miles east).
What’s near New Marston
In New Marston, that means homes and buildings near English Faculty Library, Cheney School and Headington Hill Park and the streets around them. Nearby too are Rye St Antony School (0.5 miles south-east) and White Horse pub (0.8 miles south-east). For rail, the closest station is Oxford station, about 1.6 miles south-west of the centre. Other landmarks nearby include Clarendon Shopping Centre (1.2 miles south-west) and Churchill Hospital (0.7 miles east). Open spaces near New Marston include Headington Hill and CS Lewis Nature Reserve.
Signs you need sand mastic in New Marston
Scraping and sanding before painting can loosen old mastic. Many people find it crumbling when they prepare the windows.
The problems people usually mention when they call include:
- A silicone bead on a sash window that spoils the look
- Draughty sash windows at the surround
- Failed mastic on an exposed elevation
- Cement or filler used on old window joints that has cracked
Rented homes near Oxford station change hands often, and cracked sand mastic around sash windows lets in the draughts tenants complain about.
What your quote should include
- What happens if they find a problem under the old sealant
- What the cure time is
- What preparation is included
- What the quote includes, VAT included or not
What affects the cost of sand mastic
The price is agreed before any work begins. It takes into account:
- Whether old sealant or filler has to be cut out
- How easy the joints are to reach
- Working hours on commercial sites
- The size of the job
The cost depends on the size of the job, how much old material has to come out and how easy the joints are to reach. You’ll have a clear quote before any work starts, so you know where you stand.
What to tell us for a quote
Photos by email are helpful but not essential. Try to tell us:
- What the problem is, such as mould, gaps, leaks or cracking
- Where the property is
- The type of property
- How many joints, rooms or windows are involved
The more we know about the job, the more useful the quote. Let us know the location, the problem and roughly how many joints, and add pictures by email if you can.
What happens if it’s left?
New mastic over crumbling mastic will not hold. We remove the loose material first so the new work lasts. In a smaller place like New Marston, wherever a wall is exposed, a failed outside joint is a real source of damp. Inside, a split seal lets water into floors and panels just as it would anywhere.
A failed joint rarely gets cheaper to fix by waiting. If you’re unsure, phone 0345 464 0079 or send us an email and we will give you an honest view and a quote.
Why New Marston customers choose us
- We never seal over old sealant
- Quality sealants from Arbo and Everbuild
- Every job guaranteed for a year
- Experience in homes, commercial sites and hotels
Read our cost guide and what customers say.
DIY sealant or a professional job?
The difference is mostly in the preparation and the product. Joints are cleaned back to sound surfaces and dried, and the sealant is matched to the joint and its conditions.
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.