Hertfordshire · England
Deacon's Hill Window Mastic
Mastic around window and door frames, sills and patio doors for homes and businesses in Deacon's Hill and across Hertfordshire. Fully insured, ARBOMaster approved and guaranteed for a year.
- Rain getting in at the frame or under the sill
- Draughty joints inside around the window
- Gaps left after new windows were fitted
What affects the quote in Deacon's Hill
The price is agreed before any work begins. It’s based on:
- Which sealant suits the joint
- Any working-time requirements on site
- Access and height
- Whether there’s mould to deal with
What you pay reflects the work, not guesswork. That is why we ask a few questions first.
Helping us quote
Before you ask for a quote, have a think about:
- Access, such as stairs, a lift or height
- If it’s domestic, commercial or a hotel
- The address or postcode of the job
- Pictures of the joints, sent by email
A good description makes for an accurate quote. Tell us where the job is, what’s wrong and how much there is, and add pictures by email if you can.
Window mastic in Deacon's Hill
A window frame and the wall around it expand and shrink at different rates. Plastic and aluminium frames move with the temperature, while masonry stays fairly still. That’s why the joint needs a flexible, low-modulus sealant rather than something rigid. We work on window sills, timber windows & doors and aluminium frames, and people most often call us about rain getting in at the frame or under the sill and leaking joints at the ends of sills.
Mastic can only go onto a dry, clean joint, so window work in Deacon's Hill is booked around the forecast. Tell us about access to every side of the house, including upper-floor windows.
You are covered for a year from the day we finish. If there’s a problem with it, please phone 0345 464 0079 or email us.
- Place
- Deacon's Hill (WD6)
- Wider area
- Hertfordshire
- Cover
- 12 months on all our work
- Quotes
- A clear quote up front
- Call
- 0345 464 0079
- Updated
- 26 October 2026
Nearby places to Deacon's Hill
What else we do in Deacon's Hill
Frames and glazing around Deacon's Hill
Rainfall in the South East is lower than in much of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast. With historic houses such as Headstone Manor (about 4.7 miles south-west) nearby, there’s older building stock in the area around Deacon's Hill as well as newer homes. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that’s traditional sand mastic.
Homes close to Church of St Nicholas include some older properties, and the windows may be timber, sash or later replacements, and each needs the right sealant against the wall. Schools such as Summerswood Primary School are buildings too, and the mastic around its windows and doors needs looking after like any other building’s.
Deacon's Hill is about 1 mile south of Borehamwood, in Hertfordshire. Jobs in Deacon's Hill get the same care as everywhere else we work: old sealant removed completely, careful preparation and a 12-month guarantee. Across Hertfordshire, we cover 381 places, Deacon's Hill among them. London is on our list too, about 13 miles from Deacon's Hill.
Work in WD6 is quoted and booked the same way as anywhere else. If you need window mastic at a property on Grange Road, Vale Avenue and Barnet Lane or anywhere close by, we can help. Main roads around Deacon's Hill include the A411. We also cover Edgware Bury (1 mile south), Elstree (1 mile west), Borehamwood (1 mile north), Broadfields Estate (1 mile south) and Rowley Green (2 miles north-east). Further out, we also cover Watford (5 miles west), Hemel Hempstead (11 miles north-west), St Albans (8 miles north), Welwyn Garden City (11 miles north), Harpenden (12 miles north) and Hoddesdon (14 miles north-east).
What’s near Deacon's Hill
We work in homes and buildings around Yavneh College, Edgwarebury Park and The Crown pub and the streets around them. Deacon's Hill’s nearest station is Elstree & Borehamwood station, roughly 0.6 miles north. Other landmarks nearby include Broadwalk Centre (2.2 miles south) and Royal National Orthopaedic Hospital (1.4 miles south-west). For a walk, there’s Darland's Lake and Edgware Way Grassland.
How it works
Every visit runs the same way: we look at the joints together, mask and protect the surrounding surfaces, do the work and tidy away. Most jobs take anything from an hour or two to a full day, depending on how many frames there are. Somewhere like Deacon's Hill 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.
- We check how each frame can be reached safely.
- Old, cracked mastic is removed completely.
- The surfaces are cleaned and left dry.
- Backing rod fills deep voids and the sealant goes in on top.
- We tool the joint so water runs off, then clear up.
How to prepare
- Let us know about parking restrictions
- On commercial sites, let us know about site rules
- Let us know if you’ve seen damp or leaks
Ask for a quote
We don’t publish a price list, as no two jobs are quite the same. Instead, we give you a clear price for your job. To arrange one, ring 0345 464 0079 or send us an email.
Read more
Why it’s worth doing now in Deacon's Hill
The work is quick compared with the damage it prevents: the visit takes a morning for a couple of windows and a door. Leave it until water is coming in and you may need plastering and decorating as well. In a small place like Deacon's Hill, homes can be exposed to wind and rain, which finds any gap, and older walls, once damp, take a long time to dry.
The cost depends on the size of the job, how hard the old material is to remove and how easy the joints are to reach. You will have a clear quote before any work starts, so you know where you stand.
What you get with us
- ARBOMaster approved applicator
- Anti-fungal sanitary silicone in wet areas
- Full insurance on every job
- We leave the area clean and tidy
Honest limits
We won’t take on work that won’t last, so these are the limits:
- Misting between the panes of a double-glazed unit (that needs a new unit)
- Soft or decayed wood in the frame
- A sash or casement that won’t close properly
Not sure which it is? You can call 0345 464 0079 or send us an email and we will tell you honestly before you book.
Where we work in Deacon's Hill
- Composite doors
- uPVC windows
- Timber windows & doors
- Window sills
- Patio & French doors
- Aluminium frames
DIY versus a professional finish
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. All the old material has to come out 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.
Questions from Deacon's Hill
Is Deacon's Hill within the area you cover?
Yes, Deacon's Hill is covered. Our work covers London and the South East, from towns to the smallest places. The journey is planned ahead, so it helps to know about access.
Is Deacon's Hill in your area for window mastic?
Yes. We work across London and the South East, and Deacon's Hill is part of that. You can call 0345 464 0079 or send us an email and let us know what needs doing.
Do you have sealant for grey or black windows?
Yes. White, brown, anthracite grey, black and clear sealants are all available.
Will new mastic stop draughts?
Often, yes. Air often gets in between the frame and the wall, and resealing inside and out closes it.
Where do you work from?
We are a Crawley-based firm. We work across South East England, London and Scotland.
Do you work for letting agents?
Yes, we do. We work in homes, commercial premises and hotels, and we are fully insured.
What sealant do you use?
It depends on the joint: sanitary silicone where it gets wet, and sealants suited to movement or weather elsewhere. Brands we use include Arbo and Everbuild.
Can you work on commercial sites?
Yes. Larger jobs can be planned room by room or area by area to suit the site.
Looking after it afterwards
Looking after new joints is easy:
- Keep jet washers away from the mastic
- Clear any debris from frame drain holes
- Keep timber frames painted
- Keep paint off silicone joints
Timber frames need their paint kept up, because bare, wet timber moves more and pulls at the joint. Paint up to the joint, not over the silicone.
Draughts get worse, not better. As the old mastic shrinks further, more air gets through, and heat escapes around the frame. A new joint closes it up.
Common problems we fix in Deacon's Hill
Water runs down the glass onto the sill, and the ends of the sill, where it meets the wall, are where it gets in. When that sealant fails, water gets into the wall or under the frame.
Signs it’s time to call us include:
- Mastic that has split away from the wall
- Water coming in at the bottom corners of a door
- Sealant in the wrong colour for the frame
- Rushed sealant from a window installation
If you let a flat or house near Elstree & Borehamwood station, cracked frame mastic tends to show up as a draught or damp complaint, so it’s worth checking between lets.
Comparing quotes
- Are they insured?
- The length of the guarantee
- How the colour is chosen
- Who turns up on the day