Hertfordshire · England
Holwell Window Mastic
We cover Holwell for mastic around window and door frames, sills and patio doors. Old sealant removed completely, joints prepared properly and a 12-month guarantee.
- Draughty joints inside around the window
- Draughts coming in around windows and doors
- Water coming in at the bottom corners of a door
Why deal with it now?
If you are painting or rendering, reseal at the same time. Fresh joints finish the job neatly. In a small place like Holwell, homes can be exposed to wind and rain, which finds any gap, and older walls, once damp, take a long time to dry.
Doing several joints on one visit generally makes better use of the time than several visits, so tell us about everything that needs sealing. We will give you a clear quote for the lot.
What you get with us
- Over 20 years’ experience
- You choose the colour before work begins
- A 12-month guarantee on all work
- We never seal over old sealant
Take a look at what affects the cost and our reviews.
How we handle window mastic in Holwell
Frames and walls do not move together. Plastic and aluminium frames move with the temperature, while masonry stays fairly still. So the sealant has to stretch and recover, which is why we use a low-modulus product. We work on composite doors, timber windows & doors and uPVC windows, and common reasons people get in touch are old mastic that has gone black or come away and water coming in at the bottom corners of a door.
Homes in small places like Holwell often stand in the open, with little to shelter their windows from wind and rain. Exposed frames and sills lose their mastic sooner than sheltered ones.
There’s a 12-month guarantee on every job.
- Where
- Holwell (SG5)
- Region
- Hertfordshire
- Guarantee
- 12 months on all our work
- Quote
- A clear quote up front
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
What the job involves on each surface
Patio & French doors
Patio and French doors have the longest joints on most houses. Most leaks start at the bottom corners, so they get particular care.
Composite doors
If the door itself is draughty, the issue may be the door seals or hinges rather than the frame mastic. We’ll tell you if that is what we find.
Common questions in Holwell
Can you do window mastic in Holwell?
Yes. We work across London and the South East, and Holwell is part of that. Just call 0345 464 0079 or email us with a few details of the job, and we’ll send you a clear quote.
Is Holwell within the area you cover?
Yes, we do. 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.
Can you do several jobs on one visit?
Yes. Tell us about everything you’d like done and we will quote it together.
Where are you based?
Our base is in Crawley, and we work across South East England, London and Scotland.
Will it make a mess?
Very little: the area around the joints is protected first, and we tidy up before we go.
Do you remove the old sealant?
Yes, always, and completely. New silicone doesn’t stick to old silicone, so any old material comes out before anything new goes in.
What do you need from me for a quote?
Tell us what needs doing and where. If we need more, we’ll ask.
What do you put in the joint?
We choose the sealant for the joint, not the other way round. Where it moves, gets wet or faces the weather makes a difference, and we will explain our choice.
When something else is needed
Some problems need a builder, plumber or other trade rather than us:
- Rotten timber, which needs a joiner first
- Misting between the panes of a double-glazed unit (that needs a new unit)
- Broken hinges, locks or handles
Not sure which it is? You can phone 0345 464 0079 or drop us an email and we’ll tell you honestly before booking.
Surfaces we seal
- Window sills
- Composite doors
- Patio & French doors
- Timber windows & doors
- uPVC windows
- Aluminium frames
What window mastic looks like in Holwell
Compared with the north and west, the South East gets less rain, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
Homes close to Church of St Peter (C of E) at Corner with Holwell Road include some older properties, and frames set in older brick or stone need a sealant that suits the wall as well as the frame. Letting a property close to Hitchin station? Then renewing tired window mastic between tenants heads off draught and damp complaints.
Holwell is about 3 miles north-west of Hitchin, in Hertfordshire. Our applicators cover window mastic for homes and businesses in Holwell and nearby. Holwell is one of 381 places in Hertfordshire where we work. For nearby work, see our London page.
Work in SG5 is quoted and booked the same way as anywhere else. Streets in the area include Gurney's Lane, Pirton Road and Rand's Meadow, and we cover them all. We also cover the places around Holwell: Pirton (2 miles south-west), Shillington (3 miles west), Apsley End (3 miles west), Hanscombe End (3 miles west) and Pegsdon (3 miles south-west). Within a short drive, we also cover Stevenage (7 miles south-east), Welwyn Garden City (14 miles south), Harpenden (12 miles south), Hitchin (3 miles south-east), Letchworth (3 miles east) and Letchworth Garden City (3 miles east).
Landmarks near Holwell
The nearest railway station is Hitchin station, about 2.8 miles south-east. Nearby you will also find Wymondley Castle (4.3 miles south-east) and Fairfield Hospital (2.7 miles north-east). The countryside around Holwell includes Markham's Hill and Oughtonhead Nature Reserve.
Quotes for window mastic in Holwell
Some jobs are bigger than they look, and some smaller. The main factors:
- When we can work, for business premises
- Any mould that needs treating
- How many rooms, windows or areas are involved
- Access and height
Rather than a set price list, we look at what your job involves: how many joints, what’s in them now and how we reach them. The price is agreed before we begin.
What we need to know
Photos help, but a description is a good start. Please mention:
- Photos by email, if that’s easy
- If someone has resealed it before
- How many joints, rooms or windows are involved
- The problem you’ve noticed
For a quick quote, get us on the phone, or send an email if you’d rather. Tell us about the joints that need doing and we’ll explain what’s involved and give you a clear quote.
Common problems we fix in Holwell
Older frames were often sealed with products that set hard. Once it’s rigid, every bit of frame movement pulls at it, and a gap opens along one edge.
These are the problems we are asked about most:
- Damp patches on the reveal after heavy rain
- Hard, cracked sealant around windows
- Black, perished sealant on frames
- Untidy mastic left by window fitters
For site and facilities teams at buildings such as The Priory School, its window and door frames need their mastic kept sound, just like a home’s.
What to look for in a quote
- Whether they seal over old material or remove it
- What happens if they find a problem under the old sealant
- What the cure time is
- Whether they’re fully insured
What happens on the day
We work through the job in order: protection first, then preparation, sealing and a tidy-up. For most jobs that takes anything from an hour or two to a full day, depending on how many frames there are, and the area is left clean. Somewhere like Holwell 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.
- Each frame is looked over and we agree which ones need resealing.
- We remove the old mastic and clean the frame edge and wall.
- Where the gap is deep, backing rod goes in first.
- A flexible exterior sealant is applied in a colour to suit the frame.
- Every joint is tooled smooth and checked before we leave.
Getting ready for the visit
- Let us know if you’ve seen damp or leaks
- Move anything stored near the joints
- Mention if the joints have been sealed before
Getting a quote
There’s no standard price list. Instead, we give you a clear price for your job. To arrange one, ring 0345 464 0079 or send us an email.
Advice
Should I try it myself first?
Too much sealant is as bad as too little. A heavy bead looks messy and copes badly with movement, and the joint depth matters as much as the finish.
Sealing over old silicone is the commonest DIY error. New silicone will not bond to old, so it lifts and traps water and mould underneath. Everything old must be removed first.