Hertfordshire · England
Sand mastic for sash & case windows in Radwell, Hertfordshire
Traditional burnt sand mastic around sash and case windows and doors in stone and brick for homes and businesses in Radwell and across Hertfordshire. ARBOMaster approved applicators, fully insured, with a 12-month guarantee.
- Open joints round the window box
- Crumbling sand mastic round a window
- Gaps round a timber door in stone or brick
What affects the cost of sand mastic
The quote reflects the job in front of us. We take into account:
- The number and length of the joints
- The product the joint needs
- Whether there’s mould to deal with
- Whether old sealant or filler has to be cut out
We don’t show prices on the website, because each job is priced on what it involves. Call for a quick quote and we’ll talk you through it.
What we need to know
When you call or email, it’s useful to know:
- Roughly how big the job is
- A few pictures by email, if you can
- What’s wrong with the joints now
- Any access issues, like height or stairs
For sand mastic in Radwell, ring 0345 464 0079 or send us an email. A short description of the job and where it is helps us quote, and we will agree the price before any work begins.
Sand mastic for homes and businesses in Radwell
Old sand mastic cracks, crumbles and falls out over time and gaps open up round the frame. Renewing it closes the gap so the surround looks right again. Common call-outs are for patchy fillers round a sash window and mastic round period door frames that has failed, across sash and case windows, period & listed homes and brick reveals.
In a village or hamlet like Radwell, older cottages and farmhouses often have timber windows set in stone or brick. Not every older frame suits a modern silicone bead, and sometimes a traditional sand mastic is the better choice.
A one-year guarantee comes with the work, just as it does everywhere we cover.
- Location
- Radwell (SG7)
- Region
- Hertfordshire
- Cover
- A year, on every job
- Quote
- A clear price before work begins
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
Places near Radwell
More services for Radwell
Aftercare tips
After the cure time, these simple habits help:
- Renew mastic before redecorating the windows
- Keep sills and gutters clear so water drains away
- Get any rot dealt with first
- Check the mastic when you check the paintwork
Do not touch or press the mastic while it hardens. It forms a skin fairly soon, but takes longer to harden fully.
Renewing mastic before redecorating saves doing it twice. Paint over cracked mastic only covers it up.
Your questions about sand mastic in Radwell
Can you help a landlord with a rental near Baldock station?
Yes, we work for landlords and agents. You can ring 0345 464 0079 or send us an email with the address and a few details, and we’ll give you a fixed price before we start.
Can you do sand mastic in Radwell?
Yes. Our work covers London and the South East, and Radwell is part of that. Just ring 0345 464 0079 or drop us an email with a few details of the job, and we’ll give you a clear price.
Do I need to be at home?
It depends on the job. For work indoors, someone needs to let us in, while outside work can sometimes be arranged differently.
Do you hold any approvals?
Yes. ARBOMaster is the approved applicator scheme for Arbo sealants, and we are part of it.
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. We use products from 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.
Is it OK to seal over old sealant?
No, and we never do. It may look fine at first, but the new bead soon lifts. The old sealant has to come out completely.
Do you guarantee sand mastic work?
You get our one-year guarantee on every job.
Frames and glazing around Radwell
With historic houses such as Hinxworth Place (about 2.4 miles north) nearby, there’s older building stock in the area around Radwell as well as newer homes. Where a home is older, older timber frames in brick or stone need a different approach from a modern uPVC window. The South East is one of the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
For landlords with property near Baldock station, older sash windows in a rental need their mastic kept sound to keep the weather out. If you live in an older home near Church of All Saints, replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint.
Radwell is about 2 miles north of Letchworth, in Hertfordshire. If you need sand mastic in Radwell, it’s easy to get a quote: please call 0345 464 0079 or email us. We’re based in Crawley and cover Hertfordshire, Radwell included. We cover 381 towns and villages across Hertfordshire, from the larger towns to small villages. Our London page covers work nearby, about 35 miles away.
Work in SG7 works the same way as everywhere else we cover. If you need sand mastic at a property on Radwell Lane and The Limes or anywhere close by, our applicators can take on the job. We also cover Stotfold (1 mile west), Stotfold Common (2 miles north-west), Fairfield (2 miles west) and Astwick (2 miles north-west). Larger places within reach include Stevenage (7 miles south), Welwyn Garden City (14 miles south), Harpenden (15 miles south-west), Hitchin (5 miles south-west), Hertford (15 miles south) and Ware (15 miles south-east).
Near you in Radwell
Around Radwell, our work takes us to homes and buildings near The Knights Templar School, Norton School and The Chequers Public House and the streets around them. For rail, the closest station is Baldock station, about 1.2 miles south-east of the centre. Nearby you’ll also find Bygrave House (2 miles east) and Fairfield Hospital (1.9 miles west). The countryside around Radwell includes Arlesey Old Moat and Glebe Meadows.
What happens if it’s left?
Filling over old, loose mastic doesn’t last. Raking out and preparing the joint gives it a sound base so the new work lasts. Around Radwell, older homes often have timber in their floors and frames, and water through a failed joint can rot timber if it’s left.
Homes and businesses are quoted the same way: the amount of work, the access and the products needed. Ask us for a quote and we’ll explain what it covers.
Why us?
- Anti-fungal silicone where joints get wet
- A 12-month guarantee on all work
- An ARBOMaster approved applicator
- Any old sealant cut out fully, not covered over
See what affects the cost and our reviews.
Can I do it myself?
Some sealant jobs are within reach of a careful DIYer, like a short, easy-to-reach joint indoors. The common mistakes are sealing over old sealant, sealing a damp joint and using far too much.
If you do try it yourself, take your time over the preparation: remove every trace of old sealant, clean and dry the joint, and follow the product’s cure time. If it fails, we can still redo it.
When to call us in Radwell
Water gets into small cracks in the mastic and pushes it out. Exposed elevations usually fail first.
Common reasons people contact us are:
- Mastic dropping out of the joint
- Gaps round a timber door in stone or brick
- Weathered mastic on the most exposed windows
- Patchy fillers round a sash window
If you look after a building such as Norton St Nicholas CofE (VA) Primary School, the mastic around its windows and doors needs looking after like any other building’s.
Questions to ask before you book
- Which sealant they’ll use, and why
- How long the guarantee is
- What preparation is included
- Whether they seal over old material or remove it
What the job involves on each surface
Stone surrounds
The stone is treated with care when the old mastic comes out.
Sash and case windows
The box of a sash and case window sits in the stone or brick opening. Sand mastic seals the joint round it.
How the visit works
A visit follows a simple pattern: we look at the joints together, mask and protect the surrounding surfaces, carry out the job and tidy away. It generally takes a few hours per window, depending on the condition of the joints. In a small place like Radwell, access is generally the main thing to plan. If the job is outside, mention outbuildings, exposed walls and how to reach them.
- First we agree which joints need doing.
- Old mastic and any loose material are raked out.
- 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.
Getting ready for the visit
- Tell us if parking is tricky
- Tell us about access, such as stairs, a lift or high-level joints
- Let us know if you’ve seen damp or leaks
Get a quote
Getting a quote is simple: let us know the job and the location, and roughly how big it is. A few pictures by email make the job easier to understand, and we will come back to you with a quote.