Hertfordshire · England
Sand mastic for sash & case windows in Charlton, Hertfordshire
Window and door surrounds in Charlton need attention? We remove the old material, prepare the joints and seal them properly, with a 12-month guarantee.
- Failed mastic on an exposed elevation
- A silicone bead on a sash window that spoils the look
- Gaps between timber frames and stone or brick
How it works
A visit follows a simple pattern: we check the joints, mask and protect the surrounding surfaces, carry out the job and tidy away. Most jobs take anything from a few hours to a full day, depending on how many windows. For a village or hamlet like Charlton, the journey is planned in advance: tell us about narrow lanes, gates, long drives and where we can park. Everything for the job comes with us, so a second trip is avoided where possible.
- We check the window surrounds and agree which joints need renewing.
- We rake out the old mastic and clean the joint.
- Deep voids are packed so the mastic is the right thickness.
- We mix the sand mastic and apply it by hand, shaping it to the joint.
- We dress the surface so it sits neatly against the masonry.
Before we arrive
- On commercial sites, let us know about site rules
- Move anything stored near the joints
- Where the joints are inside, avoid wetting them before we arrive
Ask for a quote
We don’t publish a price list. Instead, we give you a clear price for your job. To get started, phone 0345 464 0079 or email us.
Related advice
How we handle sand mastic in Charlton
Across Charlton, we renew sand mastic around sash and case windows. Every joint is cleaned out and filled by hand, finished to suit the masonry. Common call-outs are for silicone on a period window that looks wrong and gaps round a timber door in stone or brick, across sash and case windows, stone surrounds and period & listed homes.
Outdoor sealant needs dry, clean surfaces, so work on frames around Charlton is planned for dry weather. Let us know about access to all the frames, upstairs ones included.
The work is covered for a year after we finish. If there’s a problem with it, please phone 0345 464 0079 or email us.
- Where
- Charlton (SG5)
- Wider area
- Hertfordshire
- Guarantee
- 12 months on all our work
- Price
- Quoted before any work starts
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
Surface by surface
Brick reveals
Sand mastic is also used where timber frames meet brick. It gives a traditional finish.
Stone surrounds
The stone is treated with care when the old mastic comes out.
Quotes for sand mastic in Charlton
The quote reflects the job in front of us. We look at:
- Working hours on commercial sites
- The number and length of the joints
- The number of rooms or windows
- How much old sealant there is and how hard it is to remove
Some things make a job bigger or smaller: how much old sealant there is and how stubborn it is, whether mould needs treating, and whether we need extra access for height. We take all of that into account in your quote.
What we need to know
The more you tell us, the more accurate the quote. When you ask for a quote, tell us:
- The address or postcode of the job
- The type of property
- A few photos by email, if you can
- The rough size of the job
For sand mastic in Charlton, call 0345 464 0079 or send us an email. Tell us what the problem is and where, and we’ll agree the price before any work begins.
More services for Charlton
Questions from Charlton
Can you help a landlord with a rental near Hitchin station?
Yes, landlords and agents are among the people we work for, and several properties can be quoted together. You can ring 0345 464 0079 or send us an email with the details for a clear quote.
Do you cover Charlton for sand mastic?
Yes, Charlton is within the area we cover. Our work covers London and the South East. You can call 0345 464 0079 or email us and let us know what needs doing, and we will send you a clear quote.
Will there be a smell?
There can be a smell while the sealant cures, which fades as it sets. Opening a window helps.
What exactly is sand mastic?
It’s the traditional filler for the joint round timber windows and doors. It’s made with sand and a linseed-oil-based binder.
Will the old sealant be removed?
Always. Sealing over old sealant is the main reason resealing fails early, so we never do it.
Is it worth trying it myself?
Sometimes. Preparation is everything: all the old sealant out, and a clean, dry joint. We can always put it right if it fails.
What do you put in the joint?
We choose the sealant for the joint, not the other way round. Where it moves, gets wet or faces the weather makes a difference.
What do you need from me for a quote?
Just the basics: the address or postcode, what’s wrong and any access issues. Then ring 0345 464 0079 or send us an email.
Landlords, agents and businesses in Charlton
Water getting past a failed joint can damage the building, which matters even more when someone else lives there. Resealing at the right time is simple maintenance.
From a single let to a portfolio, you get the same standard of work: old sealant fully removed, joints prepared properly and a 12-month guarantee.
Can I do it myself?
Sealing over old silicone is the commonest DIY error. Silicone does not stick to old silicone, so it peels away and traps moisture behind it. All the old material has to come out first.
Not every job suits DIY: high-level joints, fire-rated gaps, external movement joints and big jobs call for the right materials, safe access and experience.
How to look after the new joints
No joint lasts for ever, but care makes a real difference. A few tips:
- Find out about consent before window work on a listed home
- Keep modern sealant off the mastic
- Clear gutters so water does not pour onto the windows
- Plan mastic work ahead of painting
Check the mastic when you check the paintwork. Small cracks are easier to deal with early.
Small cracks are a sign the mastic is ageing. Renewing it then is simpler than waiting until it falls out.
What sand mastic looks like in Charlton
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 an older house near a landmark such as St Mary's Church, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall. Managing a site like Highbury Infant School and Nursery? Then larger buildings have plenty of frames, and the mastic around each one ages.
Charlton is about 1 mile south-west of Hitchin, in Hertfordshire. Homes, rented property, offices and hotels in Charlton can book us for sand mastic. Every job comes with our one-year guarantee. Our area takes in 381 places across Hertfordshire. We also work in London, about 31 miles from Charlton.
We work across the SG5 postcode area for sand mastic. If you’re just outside Charlton, we cover Gosmore (1 mile south-east), Hitchin (1 mile north-east), Benslow (1 mile north-east), Bearton (1 mile north) and Westmill (1 mile north). Further out, we also cover Hemel Hempstead (15 miles south-west), Stevenage (5 miles south-east), St Albans (13 miles south), Welwyn Garden City (11 miles south), Harpenden (9 miles south) and Hatfield (12 miles south).
Near you in Charlton
We work in homes and buildings around Hitchin Boys' School, The Three Moorhens Public House and Kingshott School. Charlton’s nearest station is Hitchin station, roughly 1.4 miles north-east. Nearby you will also find North Hertfordshire Museum (0.8 miles north-east) and Lister Hospital (3.3 miles east). For a walk, there’s Markham's Hill and Oughtonhead Nature Reserve.
Do you need sand mastic in Charlton?
Decorating can disturb tired mastic. It’s often found when windows are being prepared for paint, which is a good time to renew it.
People normally contact us after spotting one of these:
- Old cement repairs round a window that have failed
- Tired mastic found when preparing windows for paint
- Mastic worn away on windows facing the weather
- Mastic dropping out of the joint
If you let a flat or house near Hitchin station, older sash windows in a rental need their mastic kept sound to keep the weather out.
Comparing quotes
- How much experience the applicator has
- What preparation is included
- Whether you can choose the colour
- The length of the guarantee