Surrey · England
Sand mastic for sash & case windows in Bishopsgate, Surrey
We cover Bishopsgate 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 12-month guarantee.
- Modern sealant on a period surround
- Gaps where the frame meets the masonry
- Draughts and rain around sash boxes
About our sand mastic in Bishopsgate
Sand mastic skins over fairly quickly but full hardening takes longer. Traditional guidance is not to paint over it and we’ll advise if you are redecorating. If you are dealing with cement or filler used on old window joints that has cracked and silicone on a period window that looks wrong, we can help.
In a village or hamlet like Bishopsgate, older cottages and farmhouses often have timber windows set in stone or brick. Older buildings like these don’t always suit modern silicone, and sometimes a traditional sand mastic is the better choice.
All our work comes with our 12-month guarantee, wherever you are in Surrey.
- Where
- Bishopsgate (TW20)
- Wider area
- Surrey
- Cover
- One year on every job
- Quote
- A clear price before any work starts
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
The process
The work is kept neat and contained to the joints we are treating. Expect the work to take a few hours per window, depending on the condition of the joints. For a village or hamlet like Bishopsgate, the journey is planned in advance: let us know about lanes, gates and parking. Everything for the job comes with us, so a second trip is avoided where possible.
- Each surround is checked first.
- We rake out the old mastic and clean the joint.
- We fill deep gaps so the new mastic isn’t too thick.
- We point the joint with sand mastic by hand.
- We finish the mastic to a tidy line.
Preparing for the visit
- Mention any parking rules near the property
- Where the joints are inside, avoid wetting them before we arrive
- Clear the area around the work
Ask for a quote
For a quick quote, get us on the phone, or send an email if you’d rather. Tell us about the joints that need doing and we will talk you through the work.
Advice
Common questions in Bishopsgate
Do you cover Bishopsgate for sand mastic?
Yes, Bishopsgate is within the area we cover. We work across London and the South East. Just phone 0345 464 0079 or email us with a few details of the job, and we will give you a clear quote.
Do you work for landlords with property near Egham station?
Yes, landlords and agents are among the people we work for, and several properties can be quoted together. Just call 0345 464 0079 or send us an email with the address and what needs doing, and we will give you a clear quote.
Is it worth trying it myself?
For a simple, easy-to-reach joint, a careful DIYer can do a reasonable job. Most DIY failures come from sealing over old material, wet joints or too much sealant.
Can you seal over the old sealant?
No. Fresh sealant does not stick to old sealant, and anything trapped underneath, including mould and water, stays there. It all has to come out first.
Will the old sealant be removed?
Yes, always, and completely. New silicone doesn’t stick to old silicone, so any old material comes out before anything new goes in.
Do I need permission for sand mastic on a listed building?
It’s best to ask your local planning authority first. Sand mastic is often favoured as like for like but the decision is theirs.
What should I tell you?
Tell us what needs doing and where, plus photos if you have them. If we need more, we will ask.
How much does sand mastic cost in Bishopsgate?
It depends on the job, so we quote each one individually. To get one, phone 0345 464 0079 or drop us an email and tell us what needs doing and where.
Different surfaces, different methods
Period and listed homes
On a listed home or in a conservation area, the right material matters. Like-for-like sand mastic is normally favoured.
Tenement and terrace windows
In shared buildings, the windows may be part of a wider repair so it’s worth checking responsibilities.
Places near Bishopsgate
Other services in Bishopsgate
Sand mastic in Bishopsgate: local notes
London and the South East are among the drier parts of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast. With historic houses such as Frogmore House (about 2.5 miles north) nearby, there’s older building stock in the area around Bishopsgate as well as newer homes. 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.
If you live in an older home near Royal Chapel of All Saints, the joint between an old wall and a newer frame is generally the first place rain gets in. If you look after a building such as St John's Beaumont School, larger buildings have plenty of frames, and the mastic around each one ages.
Bishopsgate is about 2 miles north-west of Egham, in Surrey. From the centre of Bishopsgate to the outskirts, sand mastic is available for homes and businesses alike, from flats and houses to offices and hotels. 395 places in Surrey are on our list, large and small. We also work in Reading, around 17 miles away.
Every address in TW20 is within our area for sand mastic. If you need sand mastic at a property on Bishopsgate Road, Ridgemead Road and Wick Lane or anywhere close by, we can help. We also cover Englefield Green (1 mile south-east), Egham Wick (1 mile south), Old Windsor (1 mile north), Wraysbury (2 miles north-east) and Egham (2 miles south-east). Larger places within reach include Guildford (13 miles south), Woking (9 miles south), Camberley (10 miles south-west), Epsom (15 miles south-east), Ewell (15 miles south-east) and Walton-on-Thames (9 miles south-east).
Near you in Bishopsgate
Locally, jobs take us to homes and businesses close to The Barley Mow Public House, Englefield Green Infant School and Nurseries and Windsor Great Park. The nearest railway station is Egham station, about 1.8 miles east. Well-known places in the area include Berkshire Yeomanry Museum (2.4 miles north-west) and Windsor Castle (3.2 miles north). Green spaces nearby include St Ann's Hill and Virginia Water Lake.
Signs you need sand mastic in Bishopsgate
Scraping and sanding before painting can loosen old mastic. It’s often found when windows are being prepared for paint.
These are the problems we’re asked about most:
- Draughty sash windows at the surround
- Cracked mastic round a front door frame
- Open joints round the window box
- Window mastic to renew ahead of painting
If you let a flat or house near Egham station, older sash windows in a rental need their mastic kept sound to keep the weather out.
What your quote should include
- What product goes in the joint
- When the joint can take water or movement
- Is VAT in the price?
- Is the old sealant removed completely?
Aftercare tips
A little care helps the new joints last. Our advice:
- Keep sills and gutters clear so water drains away
- Plan mastic work ahead of painting
- Find out about consent before window work on a listed home
- Avoid patching sand mastic with silicone
Avoid sealing over the mastic with silicone. If anything cracks, get it looked at rather than patching it.
Sound mastic protects the frame. Failed mastic lets water reach the timber and timber that stays wet can rot.
Why deal with it now?
An open joint round the frame lets weather in. Water can get to the frame and the masonry, so dealing with it now protects both. Older cottages and farmhouses around Bishopsgate can have timber floors and frames, where water from a failed joint can cause rot if it’s left.
What it costs depends on the size of the job, how much old material has to come out and how easy the joints are to reach. We give a clear quote before any work starts.
Why choose Mr Mastic in Bishopsgate
- 20+ years of sealant experience
- Quality sealants from Arbo and Everbuild
- Homes, businesses and hotels
- Approved under the ARBOMaster scheme
Landlord and commercial work in Bishopsgate
If you manage several properties in or around Bishopsgate, several properties can be quoted together. Just tell us the addresses and what each one needs.
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.
What sealant work can’t fix
We will not take on work that won’t last, so here’s what sealant can’t put right:
- Broken panes
- Decayed frames that need repair
- Whether work needs listed building consent
If you are not sure, just phone 0345 464 0079 or email us and we’ll give you a straight answer.
Where we work in Bishopsgate
- Tenement windows
- Period & listed homes
- Timber door frames
- Sash and case windows
- Stone surrounds
- Brick reveals