Hertfordshire · England
Sand mastic for sash & case windows in Shenleybury, Hertfordshire
Our applicators work in Shenleybury 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.
- Mastic that needs renewing before redecorating
- Mastic worn away on windows facing the weather
- Draughts and rain around sash boxes
Leave it or put it right?
Cement-based fillers and modern sealants don’t always suit a period surround. Sand mastic is the like-for-like choice and that can be important for listed homes. Older cottages and farmhouses around Shenleybury can have timber floors and frames, where water from a failed joint can cause rot if it’s left.
There are no prices on our website, because each job is priced on what it involves. Call for a quick quote and we’ll talk you through it.
What you get with us
- Anti-fungal sanitary silicone in wet areas
- Rated 4.9 stars on Google
- Tidy, careful work
- An ARBOMaster approved applicator
How we handle sand mastic in Shenleybury
Across Shenleybury, 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 modern sealant on a period surround and tired mastic found when preparing windows for paint, across period & listed homes, tenement windows and timber door frames.
Mastic can only go onto a dry, clean joint, so window work in Shenleybury is booked around the forecast. Let us know about access to all the frames, upstairs ones included.
There’s a 12-month guarantee on every job.
- Location
- Shenleybury (WD7)
- Wider area
- Hertfordshire
- Cover
- One year on every job
- Quotes
- A clear price before we start
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
What the job involves on each surface
Brick reveals
Brick reveals round timber windows are often pointed with sand mastic. It suits older brickwork.
Tenement and terrace windows
In shared buildings, the windows may be part of a wider repair so it’s worth checking responsibilities.
Sand mastic in Shenleybury: local notes
Rainfall in the South East is lower than in much of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. Historic houses like Wyllyotts Manor (about 4.1 miles east) are a reminder that the area around Shenleybury has older buildings as well as new. Where a home is older, older timber frames in brick or stone need a different approach from a modern uPVC window.
Homes close to St Botolphs include some older properties, and the windows may be timber, sash or later replacements, and each needs the right sealant against the wall. If you look after a building such as Clore Shalom School, larger buildings have plenty of frames, and the mastic around each one ages.
Shenleybury is about 3 miles north of Borehamwood, in Hertfordshire. For sand mastic in and around Shenleybury, it’s easy to get a quote: please phone 0345 464 0079 or drop us an email. We cover Hertfordshire from our Crawley base. Shenleybury is one of 381 towns and villages in Hertfordshire we cover. You can also see our page for London, roughly 16 miles from Shenleybury.
Here we cover the WD7 postcode area for sand mastic. Whether your property is on Hugo Gryn Way, Farm Close and Shenleybury or anywhere close by, we can help. Nearby, we also carry out sand mastic in Broad Colney (1 mile north-west), London Colney (1 mile north), Tyttenhanger (2 miles north), Colney Heath (3 miles north-east) and North Mymms (3 miles east). Larger places within reach include Watford (5 miles south-west), Hemel Hempstead (8 miles north-west), Stevenage (15 miles north), St Albans (4 miles north-west), Welwyn Garden City (8 miles north-east) and Harpenden (8 miles north).
What’s near Shenleybury
In Shenleybury, that means homes and buildings near The Black Lion pub, Manor Lodge School and North Mimms Park. For rail, the closest station is Radlett station, roughly 1.8 miles south-west. Other landmarks nearby include Hilfield Castle (4 miles south-west) and The Maltings (3.8 miles north-west). Green spaces nearby include Verulamium Lake and Broad Colney Lakes.
How it works
A visit follows a simple pattern: we check the joints, protect the area around them, do the work and clear up. It normally takes a few hours per window, depending on the condition of the joints. Somewhere like Shenleybury needs a little journey planning: tell us about narrow lanes, gates, long drives and where we can park. We bring what the job needs, so it can be finished in one trip where possible.
- First, we look at the surrounds with you and agree what needs doing.
- The loose and crumbling mastic is raked out and the joint cleaned.
- Large voids are packed out first, so the mastic isn’t too thick.
- The mastic is mixed, pressed into the joint by hand and shaped.
- The mastic is finished to sit tidily against the stone or brick.
Before we arrive
- Clear items away from the joints we are working on
- Mention any sign-in or site rules at work premises
- Plan for the work area to be out of bounds to pets and children
Get a quote
Asking for a quote is easy: tell us what needs doing and where, and roughly how big it is. Photos by email help us understand the job, and we’ll come back to you with a quote.
Related advice
Can I do it myself?
The difference is mostly in the preparation and the product. Joints are cleaned back to sound surfaces and dried, and the sealant is matched to the joint and its conditions.
If you’re set on DIY, put the effort into preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it fails, we can still redo it.
When to call us in Shenleybury
Timber frames move with the seasons. That movement opens up the mastic joint little by little.
These are the problems we’re asked about most:
- Mastic round period door frames that has failed
- Mastic worn away on windows facing the weather
- Silicone on a period window that looks wrong
- Mastic dropping out of the joint
Letting a property close to Radlett station? Then cracked sand mastic around sash windows lets in the draughts tenants complain about.
Comparing quotes
- Which colour the sealant will be
- Who does the work, and how experienced they are
- Whether the sealant suits the joint
- The length of the guarantee
What affects the cost of sand mastic
There’s no set price list, because no two jobs are the same. What we look at:
- The number and length of the joints
- The number of rooms or windows
- When we can work, for business premises
- Any mould that needs treating
The cost reflects the work involved, not a rough estimate. That is why we ask a few questions first and agree the price before starting.
What we need to know
To make quoting easier, let us know:
- Pictures of the joints, sent by email
- Access, such as stairs, a lift or height
- Whether it’s a home or a business
- If someone has resealed it before
We don’t publish a price list, because every job is different. Instead, we send you a clear quote for your job. To get started, ring 0345 464 0079 or drop us an email.
Shenleybury questions
Do you cover Shenleybury for sand mastic?
Yes. We work across London and the South East, and Shenleybury is part of that. You can ring 0345 464 0079 or drop us an email and let us know what needs doing.
I let a flat near Radlett station. Can you help?
Yes. We work for landlords and agents as well as householders, and several properties can be quoted together. You can call 0345 464 0079 or email us with the details for a clear quote.
Can you do several jobs on one visit?
Of course. Doing several areas at once is normally more efficient, so mention them when you ask for a quote.
What do you need from me for a quote?
Only a few details: the address or postcode, what’s wrong and any access issues. After that, simply ring 0345 464 0079 or drop us an email.
Which is right for my windows, sand mastic or modern sealant?
For period timber windows in stone or brick, sand mastic is often the better fit. Modern frames normally suit a flexible sealant.
Can I do it myself?
Sometimes. Preparation is everything: all the old sealant out, and a clean, dry joint. If it doesn’t work out, we can redo it.
Is consent needed for window work on a listed home?
Checking first is sensible. Your local planning authority can say if consent is needed for work on a listed home or in a conservation area.
What’s sand mastic made of?
It’s sand mixed with a linseed-oil-based binder for the joint between timber frames and masonry.
Towns and villages near Shenleybury
Also in Shenleybury
Keeping the joints in good condition
To keep the joints looking good and working properly:
- Get any rot dealt with first
- Take care around the mastic when scraping paint
- Renew mastic before redecorating the windows
- Clear gutters so water doesn’t pour onto the windows
Look at the mastic when you look over the windows. Catching cracks early keeps repairs small.
Crumbling mastic lets rain into the joint. It can soak into the frame and the surrounding masonry, so renewing it early is worth it.