Surrey · England
Sand mastic for sash & case windows in Farnham, Surrey
Window and door surrounds in Farnham need attention? We cut out the old, prepare the joints and apply the right sealant, with a one-year guarantee.
- Mastic round period door frames that has failed
- Window mastic to renew ahead of painting
- Old sand mastic that has cracked, crumbled or fallen out
About our sand mastic in Farnham
If your home is listed or in a conservation area, check with your local planning authority if consent is needed before window work. Sand mastic is often favoured as a like-for-like material. If you have mastic dropping out of the joint and a silicone bead on a sash window that spoils the look, we can put it right, whatever the surface.
Walls in Farnham that face the prevailing wind take the most weather, so the mastic there tends to fail first. It’s worth looking at every frame, not just the one that leaks.
You’re covered for a year from the day we finish. If anything isn’t right with it, phone 0345 464 0079 or drop us an email.
- Where
- Farnham (GU9, GU10)
- Region
- Surrey
- Cover
- A year, on every job
- Quote
- A clear quote up front
- Call
- 0345 464 0079
- Updated
- 26 October 2026
Landlord and commercial work in Farnham
Whether it’s one flat or a portfolio, you get the same standard of work: old sealant fully removed, joints prepared properly and a one-year guarantee.
Failed sealant is one of the commonest items on a check-out report. We can quote for more than one property at once.
Also near Farnham
Also in Farnham
When it is not the sealant
Some problems need a builder, plumber or other trade rather than us:
- Broken panes
- Whether work needs listed building consent
- Sashes that rattle, stick or won’t open
If you are not sure, just phone 0345 464 0079 or email us and we will give you a straight answer before you book.
What we seal
- Brick reveals
- Period & listed homes
- Sash and case windows
- Stone surrounds
- Tenement windows
- Timber door frames
FAQs for Farnham
Is sand mastic in Farnham guaranteed?
All our work, in Farnham and everywhere else, comes with a 12-month guarantee. We’re also fully insured and ARBOMaster approved.
Is Farnham in your area for sand mastic?
Yes, Farnham is within the area we cover. Our work covers London and the South East. You can phone 0345 464 0079 or drop us an email and let us know what needs doing.
What do you put in the joint?
It depends on the joint: sanitary silicone where it gets wet, and sealants suited to movement or weather elsewhere. Brands we use include Arbo and Everbuild.
Which is right for my windows, sand mastic or modern sealant?
It depends on the window. On many period windows, sand mastic looks right and suits the building, while modern frames normally get a flexible sealant.
Can I add another job to the visit?
Yes. More than one area can go on one quote.
I rent my home. Can I book you?
We are happy to deal with the tenant, landlord or agent. Get your landlord’s agreement first.
Can I choose the sealant colour?
In most cases you can choose. We will tell you which colours the right product comes in and agree one before any work starts.
Can landlords and businesses book you?
Yes, we do. Domestic, commercial and hotel work are all part of what we do, and we are fully insured.
DIY sealant or a professional job?
Not every job suits DIY: high-level joints, fire-rated gaps, external movement joints and big jobs need the right product, the right access and the right method.
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 fails, we can still redo it.
How the visit works
There isn’t much for you to do on the day. Show us the job and we will take it from there. The work itself takes a few hours per window, depending on the condition of the joints. For a job in Farnham, we need access to where the work is and somewhere nearby to park. If the job is outside, mention gates, side access and anything above ground floor.
- First we agree which joints need doing.
- We remove the old, loose mastic.
- 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.
Before we arrive
- Mention any parking rules near the property
- Let us know about stairs, lifts or work at height
- Clear the area around the work
How to get a quote
We do not publish a price list, as no two jobs are quite the same. Instead, we give you a clear price for your job. To arrange one, ring 0345 464 0079 or send us an email.
Related advice
Common problems we fix in Farnham
Over the years, sand mastic weathers. It hardens, cracks and starts to come away from the frame or the masonry.
These are the problems we’re asked about most:
- Crumbling sand mastic round a window
- Patchy fillers round a sash window
- A silicone bead on a sash window that spoils the look
- Window mastic to renew ahead of painting
If you look after a building such as Farnham College, larger buildings have plenty of frames, and the mastic around each one ages.
Before booking anyone
- How much experience the applicator has
- How hidden problems are handled
- Which colour the sealant will be
- Is the old sealant removed completely?
What affects the cost of sand mastic
Jobs vary more than people expect. What affects the quote:
- Working hours on commercial sites
- The number of rooms or windows
- The product the joint needs
- The number and length of the joints
Every job is a little different, so we quote each one individually. Size, access and the product the joint needs all play a part.
Asking for a quote
You do not need to know the technical terms. It helps if you can tell us:
- How many joints, rooms or windows are involved
- The address or postcode of the job
- If someone has resealed it before
- Pictures of the joints, sent by email
A good description makes for an accurate quote. Let us know the location, the problem and roughly how many joints, and add pictures by email if you can.
Keeping the joints in good condition
A little care helps the new joints last. Our advice:
- Look over the window mastic once a year
- Keep sills and gutters clear so water drains away
- Don’t run silicone over sand mastic
- Don’t paint over the new mastic
Leave the new mastic unpainted, as traditional guidance advises. Ask us before any decorating around it.
Gaps round a sash box let in draughts and rain. Left, the gap tends to get bigger.
Farnham homes and the weather
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 Farnham Castle (about 0.6 miles north-west) nearby, there’s older building stock in the area around Farnham as well as newer homes. In older buildings, older timber frames in brick or stone need a different approach from a modern uPVC window.
In the older streets around St Joan of Arc's Church, the joint between an old wall and a newer frame is generally the first place rain gets in. Rented homes near Farnham station change hands often, and older sash windows in a rental need their mastic kept sound to keep the weather out.
Farnham is about 6 miles south of Farnborough, in Surrey. Whether you are in the middle of Farnham or further out, sand mastic is available for homes and businesses alike. Across Surrey, we cover 395 places, Farnham among them. Reading is on our list too, around 18 miles away.
Our applicators cover all of GU9 and GU10 for sand mastic and the streets around it. If you need sand mastic at a property on Barncroft, Approach Road and Saxon Croft or a nearby road, our applicators can take on the job. With the A31 and A287 close by, Farnham is simple for us to get to for sand mastic. We also cover the places around Farnham: Compton (1 mile east), Hale (1 mile north), Upper Hale (2 miles north), Runfold (2 miles east) and Heath End (2 miles north). We also work in nearby towns such as Guildford (10 miles east), Woking (12 miles north-east), Camberley (9 miles north), Frimley (8 miles north), Haslemere (9 miles south) and Cranleigh (14 miles east). Being one of Surrey’s larger places, Farnham has homes, rented property and businesses of every kind.
Around Farnham
Around Farnham, our work takes us to homes and buildings near Moor Park, William Cobbett Public House and Weydon School. There’s a railway station in Farnham itself: Farnham station. Well-known places in the area include Museum of Farnham (under half a mile north-west) and Farnham Castle (0.6 miles north-west). For a walk, there’s Farnham Park and Aunt's Pool.