Hertfordshire · England
Sand mastic for sash & case windows in Rush Green, Hertfordshire
Traditional burnt sand mastic around sash and case windows and doors in stone and brick for householders, landlords and businesses in Rush Green. Fully insured, ARBOMaster approved and guaranteed for a year.
- Old cement repairs round a window that have failed
- Mastic that needs renewing before redecorating
- Modern sealant on a period surround
Leave it or put it right?
Gaps round a sash window let in rain and draughts. Water can get to the frame and the masonry so renewing it early protects the window. Around Rush Green, older homes often have timber in their floors and frames, and water through a failed joint can rot timber if it’s left.
Commercial jobs are quoted on the same basis as homes: the amount of work, the access and the products needed, along with when we can work on site. Call for a quick quote and we’ll explain what it covers.
Why Rush Green clients choose us
- Domestic, commercial and hotel work
- Fully insured
- Sanitary silicone with an anti-fungal additive in wet areas
- We leave the area clean and tidy
Read what affects the cost and what customers say.
Sand mastic for homes and businesses in Rush Green
Sand mastic has long been used to fill the joint between timber frames and masonry. It’s made from sand and a linseed-oil-based binder, applied by hand. On period homes, it looks right where silicone wouldn’t. If you’re dealing with gaps round a timber door in stone or brick and failed mastic on an exposed elevation, we can help, on sash and case windows, stone surrounds and brick reveals alike.
Outdoor sealant needs dry, clean surfaces, so work on frames around Rush Green is planned for dry weather. Let us know about access to all the frames, upstairs ones included.
Each job carries a 12-month guarantee, whatever its size.
- Location
- Rush Green (SG4)
- Region
- Hertfordshire
- Guarantee
- A year, on every job
- Quotes
- A clear price before work begins
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
DIY versus a professional finish
If you’ve already had a go yourself, that is fine. We cut it out and start again, so tell us about it when you ask for a quote.
The difference is mostly in the preparation and the product. We take joints back to clean, dry surfaces, and the sealant is matched to the joint and its conditions.
Questions from Rush Green
Do you cover smaller places like Rush Green?
Yes, smaller places are covered as well as towns. Our work covers London and the South East. Let us know about access, parking and anything unusual about getting there when you book.
Is Rush Green in your area for sand mastic?
Yes, Rush Green is within the area we cover. Our work covers London and the South East. You can ring 0345 464 0079 or drop us an email and tell us what needs doing.
Do you offer different sealant colours?
In most cases you can choose. We’ll explain which colours are available and agree one before we start.
Do you work for letting agents?
Yes. As well as homeowners, we work for landlords, agents, businesses and hotels across Hertfordshire.
What’s sand mastic made of?
Sand plus a binder based on linseed oil. It’s applied by hand and shaped to suit the surround.
Are you insured?
Yes. Mr Mastic is fully insured, with over 20 years’ experience in sealant work.
Can old silicone round a sash window be swapped for sand mastic?
In most cases. The silicone is cut out and the joint cleaned before the sand mastic goes in.
Are you an approved applicator?
Yes. We are an ARBOMaster approved applicator, the approved applicator scheme for Arbo sealants.
What we can’t put right
Sealant isn’t the answer to every problem, and we’d rather say so up front. Sealant will not put right:
- Damaged stone surrounds
- Rotten sashes, sills or window boxes (a joiner’s job)
- Sash cords, weights and draught-proofing of the sashes
If in doubt, call 0345 464 0079 or drop us an email and we’ll say what we think before booking.
Surfaces we seal
- Sash and case windows
- Stone surrounds
- Tenement windows
- Period & listed homes
- Timber door frames
- Brick reveals
What we do, step by step
Every visit runs the same way: we look at the joints together, mask and protect the surrounding surfaces, carry out the job and tidy away. It normally takes a few hours per window, depending on the condition of the joints. Somewhere as small as Rush Green, access is often the only tricky part. If the job is outside, mention outbuildings, exposed walls and how to reach them.
- Each surround is checked first.
- We rake out the old mastic and clean the joint.
- Large voids are packed out.
- New sand mastic is applied and shaped by hand.
- The finish is dressed neatly.
Preparing for the visit
- Let us know if you’ve seen damp or leaks
- Try not to wet indoor joints just before the visit
- Tell us if parking is tricky
Ask for a quote
We do not publish a price list. Instead, we give you a clear price for your job. To arrange one, phone 0345 464 0079 or send us an email.
Read more
Work for landlords, hotels and businesses
From a single let to a portfolio, you get the same standard of work: old sealant fully removed, joints prepared properly and a one-year guarantee.
Businesses can book us for washrooms, kitchens, offices and more. On commercial sites, working times can be discussed when we quote.
Rush Green homes and the weather
Historic houses like Knebworth House (about 2.1 miles south-east) are a reminder that the area around Rush Green has older buildings as well as new. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that is traditional sand mastic. 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 such as Knebworth House, about 2.1 miles south-east, show how far back building around Rush Green goes, and older homes nearby need a sealant that suits their walls. Letting a property close to Stevenage station? Then older sash windows in a rental need their mastic kept sound to keep the weather out. Schools such as The Thomas Alleyne School are buildings too, and larger buildings have plenty of frames, and the mastic around each one ages.
Rush Green is about 3 miles west of Stevenage, in Hertfordshire. We carry out sand mastic for homes and businesses in Rush Green. We cover 381 towns and villages across Hertfordshire, large and small. You can also see our page for London, about 28 miles away.
Every address in SG4 is within our area for sand mastic, from the main roads to the quietest streets. Nearby, we also carry out sand mastic in Langley Bottom (1 mile south), Langley (1 mile south-east), St Paul's Walden (1 mile south-west), Old Knebworth (2 miles south-east) and Whitwell (2 miles south-west). We also work in nearby towns such as Hemel Hempstead (14 miles south-west), Stevenage (3 miles east), St Albans (11 miles south), Welwyn Garden City (7 miles south), Harpenden (7 miles south-west) and Hitchin (4 miles north).
Around Rush Green
We work in homes and buildings around Concerts at Knebworth House and Farmers Boy Public House, among other places. For rail, the closest station is Stevenage station, roughly 1.6 miles east of the centre. Well-known places in the area include Lister Hospital (2.2 miles north-east) and Wymondley Castle (3 miles north). For a walk, there’s Ridlins Mire.
Nearby places to Rush Green
Other services in Rush Green
How to look after the new joints
No joint lasts for ever, but care makes a real difference. Our tips:
- Take care around the mastic when scraping paint
- Find out about consent before window work on a listed home
- Get any rot dealt with first
- Don’t run silicone over sand mastic
Leave the new mastic alone while it firms up. It forms a skin fairly soon, but takes longer to harden fully.
Sound mastic protects the frame. Once it fails, water can sit against the timber, which can lead to rot.
Surface by surface
Period and listed homes
Materials matter on listed and conservation-area homes. Sand mastic is often the preferred finish.
Timber door frames
Doors face weather and wear and the mastic can crack early. We rake it out and renew it.