Hertfordshire · England
Sand Mastic in Borehamwood
Window and door surrounds in Borehamwood need attention? We remove the old material, prepare the joints and seal them properly, and the work is guaranteed for a year.
- Gaps between timber frames and stone or brick
- Modern sealant on a period surround
- Tired mastic found when preparing windows for paint
Sand mastic in Borehamwood, done properly
Sand mastic doesn’t last for ever and gaps open up round the frame. Renewing it closes the gap so the surround looks right again. We work on stone surrounds, sash and case windows and tenement windows, and people most often call us about mastic dropping out of the joint and a silicone bead on a sash window that spoils the look.
Walls in Borehamwood that face the prevailing wind take the most weather, and that’s generally where the sealant gives up first. Checking every frame, not just the obvious one, is time well spent.
Each job carries a 12-month guarantee, whatever its size.
- Where
- Borehamwood (WD6)
- Region
- Hertfordshire
- Cover
- One year on every job
- Quotes
- A clear price before any work starts
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
How it works
We work through the job in order: protection first, then preparation, sealing and a tidy-up. For most jobs that takes a few hours per window, depending on the condition of the joints, and the area is left clean. For a job in Borehamwood, we need access to where the work is and somewhere nearby to park. If the job is outside, mention gates, side access and anything above ground floor.
- First, we look at the surrounds with you and agree what needs doing.
- We rake out the old mastic and clean the joint.
- We pack any deep gaps so the mastic sits at the right depth.
- The mastic is mixed, pressed into the joint by hand and shaped.
- The finish is dressed so it sits neatly against the stone or brick.
Preparing for the visit
- Tell us about any previous sealing or DIY attempts
- Plan for the work area to be out of bounds to pets and children
- Mention any leaks or damp you’ve noticed
Getting a quote
For a quick quote, get us on the phone, or email us if that’s easier. Tell us about the joints that need doing and we will explain what’s involved before giving you a price.
Read more
What affects the quote in Borehamwood
Call for a quick quote. What matters most is:
- The number of rooms or windows
- Access and height
- The product the joint needs
- The size of the job
A few things move the cost up or down: the old material and how easily it comes out, whether mould needs treating, and whether we need extra access for height. We take all of that into account in your quote.
Helping us quote
What to tell us when you ask for a quote:
- The rough size of the job
- Where the property is
- Pictures of the joints, sent by email
- Whether it’s a home or a business
There’s no standard price list. Instead, we send you a clear quote for your job. To arrange one, phone 0345 464 0079 or drop us an email.
DIY versus a professional finish
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 doesn’t work out, we can still put it right.
Some jobs are best left to a professional: high-level joints, fire-rated gaps, external movement joints and big jobs call for the right materials, safe access and experience.
What happens if it’s left?
New sash windows are a major, costly change and on a listed home, consent may be needed. Where the frames are in good order, new mastic seals the surround. Gaps in sealant and mould in the bead never get better on their own, and in a busy household in Borehamwood they spread with every shower and every downpour. Now is the easy time to put it right.
Instead of a standard rate, we look at what your job involves: the amount of work, the old material and the access. You’ll know the price before we begin.
Why book with us
- ARBOMaster approved applicator
- Over 20 years’ experience
- Anti-fungal silicone where joints get wet
- Domestic, commercial and hotel work
Take a look at how sealant jobs are priced or customer reviews.
How the job changes by surface
Brick reveals
Sand mastic is also used where timber frames meet brick. It gives a traditional finish.
Stone surrounds
We take care not to mark the stone when the old mastic comes out.
Borehamwood: your questions answered
Is there a guarantee on sand mastic in Borehamwood?
All our work, in Borehamwood and everywhere else, comes with a 12-month guarantee. We are also fully insured and ARBOMaster approved.
Do you work for landlords with property near Elstree & Borehamwood station?
Yes, landlords and agents are among the people we work for, and several properties can be quoted together. Just ring 0345 464 0079 or email us with the address and what needs doing, and we will send you a clear quote.
What is sand mastic?
It’s a mix of sand and a linseed-oil-based binder. It’s built up in the joint by hand and finished to sit neatly against the masonry.
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.
Can I choose the sealant colour?
We help you choose a colour that suits. The choice depends on the product the joint needs.
Can old silicone round a sash window be swapped for sand mastic?
Often, yes. With the silicone removed and the joint cleaned we point it with sand mastic.
Is it messy?
No. We protect the surfaces around the joints, and we clear up the old sealant and our materials before we leave.
How much does sand mastic cost in Borehamwood?
Size, access and the old material all affect the cost. Call for a quick quote and we’ll talk you through it.
Towns and villages near Borehamwood
Also in Borehamwood
Looking after it afterwards
After the cure time, these simple habits help:
- Have rotten timber repaired before new mastic goes in
- Renew mastic before redecorating the windows
- Inspect the joints round the windows every year or so
- Find out about consent before window work on a listed home
Avoid painting over the new mastic, which is the traditional advice. If you are redecorating, ask us first.
Renewing mastic before redecorating saves doing it twice. Painting over failed mastic hides the problem for a while.
Windows and doors in Borehamwood
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 Wyllyotts Manor (about 4.3 miles north-east) nearby, there’s older building stock in the area around Borehamwood as well as newer homes. In older buildings, older timber frames in brick or stone need a different approach from a modern uPVC window.
For landlords with property near Elstree & Borehamwood station, older sash windows in a rental need their mastic kept sound to keep the weather out. For site and facilities teams at buildings such as St Teresa Catholic Primary School, the mastic around its windows and doors needs looking after like any other building’s. If you live in an older home near All Saints church, the joint between an old wall and a newer frame is generally the first place rain gets in.
Borehamwood is about 5 miles east of Watford, in Hertfordshire. We provide sand mastic to householders, landlords and businesses in Borehamwood and nearby. We cover 381 towns and villages across Hertfordshire. You can also see our page for London, roughly 14 miles from Borehamwood.
Postcode districts we cover here for sand mastic: WD6. If you need sand mastic at a property on Station Road, Canterbury Road and Eldon Avenue or anywhere close by, we can help. Borehamwood is on the A1 and A5135, so it’s easy for us to get to with everything needed for sand mastic. Other places close to Borehamwood include Well End (1 mile north-east), Green Street (1 mile north), Deacon's Hill (1 mile south), Rowley Green (1 mile east) and Elstree (2 miles south-west). Within a short drive, we also cover Watford (5 miles west), Hemel Hempstead (10 miles north-west), St Albans (7 miles north), Welwyn Garden City (10 miles north), Harpenden (11 miles north) and Hoddesdon (13 miles north-east).
Near you in Borehamwood
Around Borehamwood, our work takes us to homes and buildings near Aldenham Country Park, The Pick & Shovel pub and Yavneh College. The closest station to Borehamwood is Elstree & Borehamwood station, about 0.6 miles south-west. Nearby you will also find Royal National Orthopaedic Hospital (2.4 miles south-west) and Spires Shopping Centre (3.1 miles east). Green spaces nearby include Darland's Lake and Rowley Lodge Field.
What we cannot put right
A few problems are outside what sealant work can do:
- Decayed frames that need repair
- Crumbling stone or brickwork round the window
- Cracked or broken glass
Not sure which it is? You can call 0345 464 0079 or email us and we will tell you honestly before booking.
Surfaces we seal
- Timber door frames
- Tenement windows
- Period & listed homes
- Sash and case windows
- Brick reveals
- Stone surrounds