Hertfordshire · England
Sand mastic for sash & case windows in Throcking, Hertfordshire
Window and door surrounds in Throcking need attention? We cut out the old, prepare the joints and apply the right sealant.
- Old sand mastic that has cracked, crumbled or fallen out
- Gaps round a timber door in stone or brick
- Gaps between timber frames and stone or brick
Can I do it myself?
A DIY attempt doesn’t rule out a professional job. We cut it out and start again, so just mention it when you contact us.
A careful DIYer can reseal a simple joint, 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.
How we handle sand mastic in Throcking
Traditional burnt sand mastic that sits naturally against stone and brick. It’s a good fit for period properties, where modern sealant can look out of place. If you have old sand mastic that has cracked, crumbled or fallen out and a silicone bead on a sash window that spoils the look, we can help, on tenement windows, period & listed homes and sash and case windows alike.
Outdoor sealant needs dry, clean surfaces, so work on frames around Throcking is planned for dry weather. Tell us about access to every side of the house, including upper-floor windows.
You get a 12-month guarantee, the same in Throcking as everywhere else we work.
- Location
- Throcking (SG9)
- Wider area
- Hertfordshire
- Cover
- A year, on every job
- Quote
- A clear quote up front
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
Looking after it afterwards
After the cure time, these simple habits help:
- Keep modern sealant off the mastic
- Make sure water runs off the sill
- Go gently near the mastic when preparing windows
- Inspect the joints round the windows every year or so
Avoid painting over the new mastic, as traditional guidance advises. If you’re redecorating, ask us first.
Once mastic starts to crumble, rain gets in. That water can reach the timber frame and the wall, so renewing it early is worth it.
Other services in Throcking
What sand mastic looks like in Throcking
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.
Homes close to Holy Trinity Church include some older properties, and replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint. For site and facilities teams at buildings such as Freman College, its window and door frames need their mastic kept sound, just like a home’s.
Throcking is about 6 miles north-east of Stevenage, in Hertfordshire. Throcking gets the same service as everywhere we cover: old sealant removed completely, careful preparation and a one-year guarantee. Throcking is one of 381 towns and villages in Hertfordshire where we work for sand mastic. Our Chelmsford page covers work nearby, about 28 miles away.
Our applicators cover all of the SG9 postcode area for sand mastic and the streets around it. We also cover the places around Throcking: Cottered (1 mile south-west), Chipping (1 mile north-east), Buntingford (2 miles east), Aspenden (2 miles south-east) and Layston (2 miles east). Further out, we also cover Stevenage (6 miles south-west), Bishop's Stortford (11 miles south-east), Welwyn Garden City (12 miles south-west), Hitchin (9 miles west), Hoddesdon (14 miles south) and Hatfield (15 miles south-west).
Landmarks near Throcking
Other landmarks nearby include Clothall Castle (4.1 miles west). Not far away are Hawkins Wood.
What we do, step by step
When we get to you, we check the joints match what you told us. If we find something unexpected, we talk it through with you first. Most jobs then take a few hours for a single window, longer for several. Somewhere like Throcking needs a little journey planning: let us know about lanes, gates and parking. Everything for the job comes with us, so a second trip is avoided where possible.
- We check each window surround and the condition of the joint.
- The joint is raked out and cleaned.
- We fill deep gaps so the new mastic is not too thick.
- We point the joint with sand mastic by hand.
- We finish the mastic to a tidy line.
How to prepare
- Let us know about earlier repairs to the joints
- Move anything stored near the joints
- On commercial sites, let us know about site rules
How to get a quote
It all starts with a short chat. Tell us what’s wrong, where it is and how much there is. When it suits you, ring 0345 464 0079 or send us an email.
Advice
What affects the cost of sand mastic
Jobs vary more than people expect. The main factors:
- How many areas need sealing
- How easy the joints are to reach
- Whether old sealant or filler has to be cut out
- Which sealant suits the joint
What you pay reflects the work, not a rough estimate. That is why we ask a few questions first.
Asking for a quote
A few details help us give you an accurate quote. When you ask for a quote, tell us:
- The address or postcode of the job
- Photos by email, if that is easy
- Roughly how big the job is
- The type of property
Asking for a quote is easy: let us know the job and the location, and roughly how big it is. A few photos by email make the job easier to understand, and we’ll take it from there.
What sealant work cannot fix
Some problems need a builder, plumber or other trade rather than us:
- Sash cords, weights and draught-proofing of the sashes
- Planning or listed building consent (your local planning authority decides)
- Masonry that needs repairing
If in doubt, call 0345 464 0079 or send us an email and we’ll say what we think.
Joints and surfaces we work on
- Tenement windows
- Timber door frames
- Sash and case windows
- Stone surrounds
- Period & listed homes
- Brick reveals
Landlord and commercial work in Throcking
Whether it’s one flat or a portfolio, you get the same standard of work: old sealant fully removed, joints prepared properly and a 12-month guarantee.
Water getting past a failed joint can damage the building, which is a bigger problem in a rented property. Keeping joints in good order is simple maintenance that we can handle for you.
How the job changes by surface
Tenement and terrace windows
Tenements and terraces often have many sash windows with ageing mastic. We work on single windows or whole elevations.
Period and listed homes
On a listed home or in a conservation area, the right material matters. Like-for-like sand mastic is normally favoured.
FAQs for Throcking
Is there a guarantee on sand mastic in Throcking?
All our work, in Throcking and everywhere else, comes with a 12-month guarantee. We are also fully insured and ARBOMaster approved.
Will you come out to Throcking?
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.
Do you work for hotels and businesses?
Yes, regularly. We can plan bigger jobs in stages.
Are you fully insured?
Yes. We are fully insured.
Do you work for landlords and businesses?
Yes. We work in homes, commercial premises and hotels.
Can I choose the sealant colour?
Yes. White, clear and grey are common, and other colours are available, and we’ll agree it with you first.
How long does sand mastic take?
Most jobs take anything from a few hours to a full day, depending on how many windows. Your quote will say how long we expect yours to take.
Does someone need to be in?
We need access to the joints, so we will agree that with you when we book. For inside work, that normally means someone being in.