Hertfordshire · England
Hay Street Sand Mastic
Sand mastic in Hay Street from a team with over 20 years’ experience. Rated 4.9 on Google from 180+ five-star reviews.
- Wind and rain getting in round a sash window
- Tired mastic found when preparing windows for paint
- Modern sealant on a period surround
Sand mastic in Hay Street
Burnt sand mastic is a traditional material that sits naturally against stone and brick. It suits period and listed homes, where modern sealant can look out of place. We work on sash and case windows, period & listed homes and brick reveals, and the jobs we see most are old cement repairs round a window that have failed and weathered mastic on the most exposed windows.
In a village or hamlet like Hay Street, 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.
There’s a 12-month guarantee on every job, large or small.
- Place
- Hay Street (SG11)
- Region
- Hertfordshire
- Cover
- 12 months on all our work
- Quotes
- Quoted before any work starts
- Call
- 0345 464 0079
- Updated
- 26 October 2026
How the job changes by surface
Stone surrounds
Sand mastic sits naturally against stone. It finishes to look like part of the surround.
Brick reveals
We rake out the old mastic and pack deep voids before pointing.
What we cannot put right
Some problems need a builder, plumber or other trade rather than us:
- Timber that has rotted
- Cracked or broken glass
- Sash cords, weights and draught-proofing of the sashes
If in doubt, call 0345 464 0079 or drop us an email and we’ll say what we think before booking.
Joints and surfaces we work on
- Stone surrounds
- Timber door frames
- Period & listed homes
- Tenement windows
- Brick reveals
- Sash and case windows
What affects the cost of sand mastic
For a quick quote, just ask. The main things that affect it are:
- Whether the work is at height
- The old material and how stubborn it is
- The type of sealant required
- How many areas need sealing
Every job is a little different, so each one gets its own quote. Size, access and the product the joint needs all make a difference, and we will explain the quote if you ask.
Asking for a quote
What to tell us when you ask for a quote:
- Roughly how big the job is
- Whether it has been sealed before
- The problem you’ve noticed
- Any access issues, like height or stairs
Asking for a quote is easy: let us know the job and the location. A few pictures by email make the job easier to understand.
How it works
A visit follows a simple pattern: we check the joints, mask and protect the surrounding surfaces, do the work and tidy away. Most jobs take a few hours for a single window, longer for several. In a small place like Hay Street, access is generally the main thing to plan. For outside work, also let us know about exposed walls and any outbuildings involved.
- We check the window surrounds and agree which joints need renewing.
- The loose and crumbling mastic is raked out and the joint cleaned.
- Large voids are packed out first, so the mastic is not too thick.
- 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.
Getting ready for the visit
- Mention if the joints have been sealed before
- Let us know about stairs, lifts or work at height
- Where the joints are inside, avoid wetting them before we arrive
Ask for a quote
Need a quote? Please ring 0345 464 0079 or send us an email with a few details. We’ll explain what we’d do and send you a clear quote before work begins.
Read more
Places near Hay Street
What else we do in Hay Street
Questions from Hay Street
What guarantee comes with sand mastic in Hay Street?
Every job comes with our 12-month guarantee, wherever it is. We’re also fully insured and ARBOMaster approved.
Is Hay Street in your area for sand mastic?
Yes. We work across London and the South East, and Hay Street is part of that. You can ring 0345 464 0079 or email us and tell us what needs doing, and we’ll give you a clear price.
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 for work to your windows.
Are you fully insured?
Yes. Mr Mastic is fully insured.
Do you do commercial work?
Yes. We’ve worked for hotels, offices and other businesses, and we’re fully insured.
What information do you need?
The location, the problem and the rough size of the job. Photos by email help too.
Is it messy?
No. We protect the surfaces around the joints, and we tidy up before we go.
What’s sand mastic made of?
A traditional pointing material made from sand and a linseed-oil-based binder for the joint between timber frames and masonry.
Why deal with it now?
Not every filler suits an old window surround. Sand mastic matches what was there, which can matter on listed and conservation-area homes. Around Hay Street, older homes often have timber in their floors and frames, where water from a failed joint can cause rot if it’s left.
A failed joint rarely gets cheaper to fix by waiting, because water and mould keep working on it. If you are unsure, call 0345 464 0079 or email us for an honest opinion and a quote.
Why Hay Street clients choose us
- Tidy, careful work
- Rated 4.9 stars on Google
- Any old sealant cut out fully, not covered over
- Full insurance on every job
Take a look at our cost guide and what customers say.
How to look after the new joints
So the new joints stay in good condition:
- Keep sills and gutters clear so water drains away
- Do not paint over the new mastic
- Check the mastic when you check the paintwork
- Avoid heavy scraping on the mastic joint
Check the mastic when you check the paintwork. Catching cracks early keeps repairs small.
Crumbling mastic lets rain into the joint. It can soak into the frame and the surrounding masonry so early renewal protects both.
Should I try it myself first?
Sealing over old silicone is the commonest DIY error. Silicone does not stick to old silicone, so it lifts and traps water and mould underneath. Everything old must be removed first.
A careful DIYer can reseal a simple joint, like a short, easy-to-reach joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
Windows and doors in Hay Street
Compared with the north and west, the South East gets less rain, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast. With historic houses such as Much Hadham Palace (about 4.7 miles south-east) nearby, there’s older building stock in the area around Hay Street as well as newer homes. In older buildings, older timber frames in brick or stone need a different approach from a modern uPVC window.
Managing a site like Jenyns First School and Nursery? Then its window and door frames need their mastic kept sound, just like a home’s. In the older streets around Parish Church of St Mary the Virgin, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Hay Street is about 7 miles north-west of Bishop's Stortford, in Hertfordshire. Whether you’re in the middle of Hay Street or further out, we cover sand mastic for every kind of property, from flats and houses to offices and hotels. Hay Street is one of 381 places in Hertfordshire we cover. Chelmsford is on our list too, around 23 miles away.
Our applicators cover all of the SG11 postcode area for sand mastic and the streets around it. We also cover the places around Hay Street: Braughing (1 mile south-east), Westmill (2 miles west), Aspenden (2 miles north-west), Great Hormead (2 miles north) and Buntingford (3 miles north-west). Further out, we also cover Stevenage (9 miles west), Bishop's Stortford (7 miles south-east), Welwyn Garden City (12 miles south-west), Hitchin (13 miles west), Hoddesdon (11 miles south) and Cheshunt (15 miles south).
Landmarks near Hay Street
Around Hay Street, our work takes us to homes and buildings near Adam And Eve Public House and the streets around them. Other landmarks nearby include Brent Pelham (3.7 miles north-east).