Hertfordshire · England
Window & door mastic in Elstree, Hertfordshire
Mastic around window and door frames, sills and patio doors in Elstree, with a 12-month guarantee on every job. Call for a quick quote.
- Whistling draughts around closed windows
- Sealant in the wrong colour for the frame
- Cracked internal joints between frame and plaster
Window mastic for homes and businesses in Elstree
Behind a thin line of old mastic there’s sometimes a deep void. Filling it with sealant alone leaves a joint that can’t move properly, so deep gaps get backing rod first. The sealant then grips the two sides it should. We’re often asked to deal with gaps between the frame and the inside reveal and gaps left after new windows were fitted, across aluminium frames, timber windows & doors and window sills.
Around Elstree, many homes face open ground, so their windows and doors take the full weather. That exposure dries out and cracks the mastic around frames and sills faster.
A 12-month guarantee comes with the work, just as it does everywhere we cover.
- Place
- Elstree (WD6)
- Region
- Hertfordshire
- Guarantee
- One year on every job
- Price
- A clear quote up front
- Call
- 0345 464 0079
- Updated
- 26 October 2026
When something else is needed
We’ll always be straight with you, so here’s what sealant cannot fix:
- Damp problems in the wall away from the window
- A door that needs adjusting, rehanging or new seals
- Misting between the panes of a double-glazed unit (that needs a new unit)
If you’re not sure, just call 0345 464 0079 or email us and we’ll give you a straight answer.
Surfaces we seal
- Window sills
- Timber windows & doors
- Aluminium frames
- uPVC windows
- Patio & French doors
- Composite doors
Should I try it myself first?
Overfilling a joint is a classic DIY mistake. A thick, smeared bead looks untidy and does not move well, and the joint depth matters as much as the finish.
What a professional job adds is preparation and the right product. Joints are cleaned back to sound surfaces and dried, and the sealant is chosen for how the joint moves and where it is, and the work is guaranteed for a year.
What the job involves on each surface
Composite doors
Composite doors are normally hung in an uPVC-type frame, so its perimeter joint is sealed much like a window. The bead is colour-matched to the frame.
Aluminium frames
Metal frames expand in the sun and are often slim, with little room for error. A neat, narrow bead in a colour to match suits the frame.
Also in Elstree
Landlord and commercial work in Elstree
We also work for property managers and facilities teams. Several sites can go on one quote.
Whether it’s one flat or a portfolio, you get the same standard of work: the old material taken out, careful preparation and a 12-month guarantee.
Leave it or put it right?
Draughts and leaks don’t always mean new windows. If the frames and glass are in good order, resealing the joints is often all that is needed. If we find failed glass units or worn seals, we’ll tell you. In a small place like Elstree, homes can be exposed to wind and rain, which finds any gap, and damp in older walls is slow to dry out.
Commercial jobs are quoted on the same basis as homes: the amount of work, how we reach it and what it needs, along with when we can work on site. Ask us for a quote and we will explain what it covers.
Why choose Mr Mastic in Elstree
- 180+ five-star Google reviews
- Homes, businesses and hotels
- Anti-fungal silicone where joints get wet
- Full insurance on every job
Take a look at how sealant jobs are priced and what customers say.
Windows and doors in Elstree
Historic houses like Headstone Manor (about 4.1 miles south-west) are a reminder that the area around Elstree has older buildings as well as new. Where a home is older, older frames set in brick or stone need a sealant that suits them, and sometimes that’s traditional sand mastic. Compared with the north and west, the South East gets less rain, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
For landlords with property near Elstree & Borehamwood station, cracked frame mastic tends to show up as a draught or damp complaint, so it’s worth checking between lets. Schools such as St Nicholas Elstree Church of England VA Primary School are buildings too, and the mastic around its windows and doors needs looking after like any other building’s. If you live in an older home near Church of St Nicholas, replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint.
Elstree is about 2 miles south-west of Borehamwood, in Hertfordshire. If you need window mastic in Elstree, it’s easy to get a quote: please call 0345 464 0079 or drop us an email. We’re based in Crawley and cover Hertfordshire, Elstree included. Our area takes in 381 places across Hertfordshire, from the larger towns to small villages. For nearby work, see our London page (13 miles or so).
Our applicators cover all of the WD6 postcode area for window mastic. Whether your property is on High Street, West View Gardens and Summer Grove or a nearby road, our applicators can take on the job. Close by, we work in Deacon's Hill (1 mile east), Edgware Bury (1 mile south-east), Broadfields Estate (2 miles south-east), Borehamwood (2 miles north-east) and Edgware (2 miles south-east). Further out, we also cover Watford (5 miles west), Hemel Hempstead (10 miles north-west), St Albans (8 miles north), Welwyn Garden City (12 miles north-east), Harpenden (12 miles north) and Hoddesdon (14 miles north-east).
Around Elstree
We work in homes and buildings around The Holly Bush pub, London Academy and Aldenham Country Park. The nearest railway station is Elstree & Borehamwood station, about 1.1 miles north-east of the centre. Well-known places in the area include Elstree and Borehamwood Museum (1.4 miles north-east) and Royal National Orthopaedic Hospital (0.8 miles south). Not far away are Darland's Lake and Edgware Way Grassland.
Looking after it afterwards
A little care helps the new joints last. We recommend:
- Avoid blasting the frames with a pressure washer
- Wipe condensation off the frames
- Clean frames with a soft cloth and soapy water
- Look round the frames every year or so
Check the drainage slots in the frames are not blocked, so water can run away instead of sitting against the joint.
On timber windows, water behind the joint can lead to rot. Rotten timber needs a joiner, not a sealant, so early resealing is worth it.
How it works
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 anything from an hour or two to a full day, depending on how many frames there are. Somewhere like Elstree needs a little journey planning: let us know about lanes, gates and parking. We bring what the job needs, so it can be finished in one trip where possible.
- We check each frame and agree which ones need doing.
- We remove the old mastic and clean the frame and the wall.
- Deep gaps are filled with backing rod to set the depth.
- New exterior sealant goes on in a matching colour and is tooled smooth.
- We clear up and check every joint is fully closed.
How to prepare
- Let us know about earlier repairs to the joints
- Clear the area around the work
- Plan for the work area to be out of bounds to pets and children
Ask for a quote
To get a quote, phone 0345 464 0079 or email us with the location and a short description of the problem. We’ll send you a clear quote before any work starts.
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Questions from Elstree
I let a flat near Elstree & Borehamwood station. Can you help?
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 drop us an email with the details for a clear quote.
Is Elstree within the area you cover?
Yes, we do. We work across London and the South East, and smaller places are part of that. Longer journeys are simply planned in advance.
How long does it take to reseal the windows on a house?
Allow anything from an hour or two to a full day, depending on how many frames there are. Access and the amount of old mastic make the biggest difference.
Will there be a smell?
Sometimes, a little. Any smell clears as the sealant cures, and ventilation helps.
Where do you work from?
Our base is Crawley. We work across South East England, London and Scotland.
Can you quote for more than one area?
Yes, and it often makes sense. Combining jobs makes good use of the visit, so mention them when you ask for a quote.
When is the sealant fully cured?
That depends on the sealant used, so please follow the time we give you.
Do you remove the old sealant?
Always. Sealing over the old bead is the commonest cause of early failure, and it’s something we never do.