Hertfordshire · England
Sand mastic for sash & case windows in Tewin Wood, Hertfordshire
Our applicators work in Tewin Wood on 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.
- Wind and rain getting in round a sash window
- Modern sealant on a period surround
- Mastic dropping out of the joint
How the job changes by surface
Brick reveals
We rake out the old mastic and pack deep voids before pointing.
Sash and case windows
The box of a sash and case window sits in the stone or brick opening. The gap round it is pointed with sand mastic.
Sand mastic in Tewin Wood
Silicone on a period window often looks wrong and is not always the right material. Sand mastic is the traditional choice and we can swap the silicone for it. If you’re dealing with draughts and rain around sash boxes and mastic round period door frames that has failed, we can put it right, whatever the surface.
Somewhere as small as Tewin Wood, older homes often have timber frames set in stone or brickwork. Not every older frame suits a modern silicone bead, so the sealant has to be chosen to suit the building.
Big or small, you get the same one-year guarantee.
- Place
- Tewin Wood (AL6)
- Wider area
- Hertfordshire
- Guarantee
- One year on every job
- Quotes
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
Also near Tewin Wood
More services for Tewin Wood
What sand mastic looks like in Tewin Wood
With historic houses such as Digswell House (about 2.1 miles south-west) nearby, there’s older building stock in the area around Tewin Wood as well as newer homes. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that’s traditional sand mastic. London and the South East are among the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
Digswell House, about 2.1 miles south-west, is one of the historic houses in the wider area around Tewin Wood, and older homes nearby need a sealant that suits their walls. For site and facilities teams at buildings such as Ridgeway Academy, the mastic around its windows and doors needs looking after like any other building’s.
Tewin Wood is about 3 miles north-east of Welwyn Garden City, in Hertfordshire. Jobs in Tewin Wood get the same care as everywhere else we work: the old material taken out, joints prepared properly and a 12-month guarantee. Tewin Wood is one of 381 places in Hertfordshire where we work for sand mastic. We also work in London, around 23 miles away.
Postcode districts we cover here for sand mastic: AL6. If you need sand mastic at a property on Cowpers Way, Desborough Drive and Firs Walk or anywhere close by, we can help. Close by, we work in Burnham Green (1 mile north-west), Bull's Green (1 mile north), Harmer Green (1 mile west), Tewin (1 mile south) and Datchworth (1 mile north). Larger places within reach include Watford (15 miles south-west), Hemel Hempstead (14 miles south-west), Stevenage (5 miles north), St Albans (9 miles south-west), Bishop's Stortford (14 miles east) and Welwyn Garden City (3 miles south-west).
Local landmarks in Tewin Wood
In Tewin Wood, that means homes and buildings near Belmont pub. For rail, the closest station is Welwyn North station, about 1.4 miles west. Well-known places in the area include Howard Centre (2.8 miles south-west) and Hertford Castle (4.3 miles south-east). Green spaces nearby include Tewin Orchard and Hopkyns Wood.
Do you need sand mastic in Tewin Wood?
Scraping and sanding before painting can loosen old mastic. It’s often found when windows are being prepared for paint, which is a good time to renew it.
Keep an eye out for any of the following:
- Mastic dropping out of the joint
- Wind and rain getting in round a sash window
- Silicone on a period window that looks wrong
- Gaps where the frame meets the masonry
If you let a flat or house near Welwyn North station, any sash windows need sound mastic to keep draughts and rain out.
Questions to ask before booking
- What preparation is included
- Whether you can choose the colour
- The length of the guarantee
- Whether the sealant suits the joint
For landlords and businesses
We also work for property managers and facilities teams. Several sites can be quoted together, and we’re fully insured for the work.
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.
How we quote for sand mastic
The quote reflects the job in front of us. We look at:
- Whether there’s mould to deal with
- Whether the work is at height
- How many areas need sealing
- When we can work, for business premises
A few things move the cost up or down: the old material and how easily it comes out, any mould to treat, and whether the work is at height. Your quote takes all of that into account.
What we need to know
When you contact us, it’s useful to know:
- How many joints, rooms or windows are involved
- If it’s domestic, commercial or a hotel
- How we’d reach the joints
- A few photos by email, if you can
Call for a quick quote, or send an email if you’d rather. Describe what needs sealing and we will explain what’s involved and give you a clear quote.
FAQs for Tewin Wood
Do you cover Tewin Wood for sand mastic?
Yes. We work across London and the South East, and Tewin Wood is part of that. Just ring 0345 464 0079 or drop us an email with a few details of the job.
Can you help a landlord with a rental near Welwyn North station?
Yes, we work for landlords and agents. Just ring 0345 464 0079 or send us an email and tell us about the property, and we will give you a clear price.
Will there be a smell?
Some sealants have a smell while they cure. Opening a window helps.
Should I try DIY first?
Sometimes. The key is preparation: remove all the old material and work on a clean, dry joint. If it does not work out, we can redo it.
What should I tell you?
Only a few details: the address or postcode, what’s wrong and any access issues. After that, simply phone 0345 464 0079 or send us an email.
Will you leave a mess?
No. The area is protected while we work and cleaned up afterwards.
How long does the job take?
Most jobs take a few hours for a single window, longer for several. Your quote will say how long we expect yours to take.
Can you do several jobs on one visit?
Yes. Just list everything you need.
How the visit works
There is not 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 for a single window, longer for several from start to finish. Somewhere as small as Tewin Wood, access is often the only tricky part. If the job is outside, mention outbuildings, exposed walls and how to reach them.
- We check each window surround and the condition of the joint.
- The joint is raked out and cleaned.
- Large voids are packed out.
- We point the joint with sand mastic by hand.
- We finish the mastic to a tidy line.
Getting ready for the visit
- Let us know if you’ve seen damp or leaks
- Mention any sign-in or site rules at work premises
- Clear items away from the joints we are working on
How to get a quote
Every job is quoted individually, so start by telling us what you need. Simply ring 0345 464 0079 or send us an email and describe the job, and pictures are welcome.
Related advice
What we cannot put right
We will not take on work that won’t last, so here’s what sealant cannot put right:
- Timber that has rotted
- Sash cords, weights and draught-proofing of the sashes
- Masonry that needs repairing
If you’re not sure, just phone 0345 464 0079 or email us and we’ll give you a straight answer before booking.
Surfaces we seal
- Tenement windows
- Brick reveals
- Stone surrounds
- Timber door frames
- Sash and case windows
- Period & listed homes
Leave it or put it right?
Gaps round a sash window let in rain and draughts. Left, water can reach the timber and the wall, so dealing with it now protects both. Where a wall is exposed, as many are in small places like Tewin Wood, wind-driven rain gets into any failed joint, and older walls, once damp, take a long time to dry.
Leaving a failed joint normally makes the job bigger, not smaller, as water and mould keep getting in. If you are unsure, phone 0345 464 0079 or email us and we will give you an honest view and a quote.
Why book with us
- Rated 4.9 stars on Google
- Homes, businesses and hotels
- An ARBOMaster approved applicator
- A 12-month guarantee on all work
See what affects the cost and our reviews.