Hertfordshire · England
Marshalswick Sand Mastic
Traditional burnt sand mastic around sash and case windows and doors in stone and brick in Marshalswick, with a 12-month guarantee on every job. Ask us for a quote.
- Failed mastic on an exposed elevation
- A silicone bead on a sash window that spoils the look
- Tired mastic found when preparing windows for paint
Sand mastic for homes and businesses in Marshalswick
Sand mastic has long been used to fill the joint between timber frames and masonry. It’s a mix of sand and a linseed-oil-based binder, applied by hand. On older homes, it suits the building far better than silicone. Typical jobs include window mastic to renew ahead of painting and silicone on a period window that looks wrong, across stone surrounds, sash and case windows and tenement windows.
Houses in smaller places like Marshalswick can stand more in the open than those in a built-up town, so exposed windows and doors face the weather head on. That is hard on the mastic around frames and sills.
You are covered for a year from the day we finish. If there’s a problem with it, please call 0345 464 0079 or send us an email.
- Place
- Marshalswick (AL4, AL1, AL3)
- Wider area
- Hertfordshire
- Guarantee
- One year on every job
- Price
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
What happens on the day
All our tools and materials come with us in the van, so there’s nothing for you to buy. Once we’ve agreed what’s being done, the area is protected and the work begins. It normally takes a few hours for a single window, longer for several. A visit to Marshalswick 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.
- Each surround is checked first.
- The joint is raked out and cleaned.
- We fill deep gaps so the new mastic isn’t too thick.
- We point the joint with sand mastic by hand.
- The finish is dressed neatly.
How to prepare
- Tell us about access, such as stairs, a lift or high-level joints
- Keep children and pets away from the work area
- On commercial sites, let us know about site rules
Getting a quote
Every job is quoted individually, so the first step is telling us about yours. Just phone 0345 464 0079 or send us an email with the details.
Related advice
Questions from Marshalswick
Do you work for landlords with property near St Albans station?
Yes, rental work is part of what we do. You can phone 0345 464 0079 or email us with the address and a few details, and we’ll give you a fixed price before any work starts.
Do you cover Marshalswick for sand mastic?
Yes, Marshalswick is within the area we cover. We work across London and the South East. You can call 0345 464 0079 or send us an email and let us know what needs doing.
Which is right for my windows, sand mastic or modern sealant?
It depends on the window. Period windows in stone or brick generally suit sand mastic and newer frames normally get a flexible sealant.
What information do you need?
Only a few details: the address or postcode, what’s wrong and any access issues. After that, simply phone 0345 464 0079 or drop us an email.
Is there any odour?
Sometimes, a little. It fades as the sealant cures, and ventilation helps.
Do you have insurance?
Yes. We are fully insured.
Can you work on commercial sites?
Yes. We work in offices, washrooms, hotels and other commercial premises. We can talk about working times when we quote.
Should I check with the council before work on a listed or conservation-area home?
Check with your local planning authority. They’ll tell you if consent is needed.
DIY versus a professional finish
Sealing over old silicone is the commonest DIY error. New silicone won’t bond to old, so it peels away and traps moisture behind it. Everything old must be removed first.
A DIY attempt does not rule out a professional job. We remove it and do the joint properly.
How the job changes by surface
Timber door frames
Door frames get knocked and soaked, so their mastic can fail sooner. It’s renewed by hand.
Period and listed homes
Many older homes were built with sand mastic round the windows. On listed buildings, check with your planning authority first.
Work for landlords, hotels and businesses
Hotels need rooms back in use, so the work can be planned room by room around your bookings where we can. Hotel work is part of what we do, alongside homes and businesses.
A neglected joint can let water reach the structure, which matters even more when someone else lives there. Resealing at the right time is simple maintenance that we can handle for you.
Towns and villages near Marshalswick
More services for Marshalswick
Frames and glazing around Marshalswick
Rainfall in the South East is lower than in much 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 Batchwood Hall (about 2 miles west) nearby, there’s older building stock in the area around Marshalswick 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.
Schools such as St John Fisher Roman Catholic Primary School are buildings too, and the mastic around its windows and doors needs looking after like any other building’s. For landlords with property near St Albans station, older sash windows in a rental need their mastic kept sound to keep the weather out.
Marshalswick is about 1 mile north-east of St Albans, in Hertfordshire. We carry out sand mastic for homes and businesses in Marshalswick, as part of our work across Hertfordshire. Marshalswick is one of 381 places in Hertfordshire where we work. There’s also a page for London, about 21 miles away.
We work across AL4, AL1 and AL3 for sand mastic and the streets around it. Local streets include Milvus Road, Jersey Lane and Sandpit Lane, all of which we cover. We also cover the places around Marshalswick: Sandridge (1 mile north), Bernards Heath (1 mile west), St Albans (1 mile south-west), Childwick Green (2 miles north-west) and Sopwell (2 miles south-west). Within a short drive, we also cover Watford (8 miles south-west), Hemel Hempstead (7 miles west), Stevenage (11 miles north-east), Welwyn Garden City (5 miles north-east), Harpenden (4 miles north-west) and Hitchin (13 miles north).
What’s near Marshalswick
Around Marshalswick, our work takes us to homes and buildings near The Baton pub, Sandringham School and Clarence Park and the streets around them. The closest station to Marshalswick is St Albans station, roughly 1.3 miles south-west. Well-known places in the area include St Albans Musical Museum (0.8 miles south-west) and The Maltings (1.6 miles south-west). Not far away are The Wick Local Nature Reserve and Verulamium Lake.
Leave it or put it right?
An open joint round the frame lets weather in. Left, water can reach the timber and the wall so renewing it early protects the window. In an older home around Marshalswick, damp from a failed joint can get into timber and plaster, which is far harder to put right than the sealant itself.
A few things move the cost up or down: the old material and how easily it comes out, whether mould needs treating, and whether the work is at height. We take all of that into account in your quote.
What you get with us
- Old sealant always removed completely
- Neat joints and a tidy finish
- Over 20 years’ experience
- Every job guaranteed for a year
What sealant work cannot fix
We’d rather tell you now than do work that won’t last, so here’s what sealant cannot put right:
- Crumbling stone or brickwork round the window
- Putty and glazing repairs
- Rotten sashes, sills or window boxes (a joiner’s job)
Not sure which it is? You can call 0345 464 0079 or email us and we’ll tell you honestly.
Where we work in Marshalswick
- Stone surrounds
- Timber door frames
- Brick reveals
- Period & listed homes
- Tenement windows
- Sash and case windows
Signs you need sand mastic in Marshalswick
Most of it is simply age. Sand mastic is a maintenance item like any pointing, depending on exposure and upkeep.
Look out for these signs:
- Crumbling sand mastic round a window
- Gaps round a timber door in stone or brick
- Window mastic to renew ahead of painting
- Old cement repairs round a window that have failed
Homes close to Saint Mary's include some older properties, and the joint between an old wall and a newer frame is generally the first place rain gets in.
What your quote should include
- What happens if the job turns out different
- When the joint can take water or movement
- How much experience the applicator has
- What preparation is included