Hertfordshire · England
External Mastic in Kemprow
We cover Kemprow for sealing brickwork movement joints, render, cladding and façade joints. Old sealant removed completely, joints prepared properly and every job guaranteed for a year.
- Plants rooting in failed movement joints
- Brick movement joints where the sealant has split
- Gaps where render, brick and frames meet
Looking after it afterwards
So the new joints stay in good condition:
- Walk round the building once a year and look at the joints
- Leave the joints unpainted unless we’ve said otherwise
- Show decorators and builders where the movement joints are
- Clear growth from the base of walls and joints
Have a quick look at the joints each spring. Splits, gaps at the edges or plants in the joint are early warning signs.
Act while the splits are small. Then it’s a straightforward cut-out and reseal.
External mastic for homes and businesses in Kemprow
On houses, flats and commercial buildings across Kemprow, we reseal joints in brickwork, render, cladding and façade panels. The preparation is the same whatever the wall: clean joint faces and the right depth. We work on copings & trims, render & cladding joints and concrete & block, and people most often call us about damp patches traced to an open external joint and weathered mastic that no longer stretches.
Around Kemprow, older buildings can be stone, brick or timber-framed, many with extensions added later. Where one material meets another is where water usually gets in, and they need the right sealant at the right depth.
A one-year guarantee comes as standard.
- Location
- Kemprow (WD25)
- Region
- Hertfordshire
- Cover
- 12 months on all our work
- Quotes
- A clear quote up front
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
Nearby places to Kemprow
Other services in Kemprow
What affects the cost of external mastic
There’s no set price list. What we look at:
- The type of sealant required
- The size of the job
- How many areas need sealing
- Whether the work is at height
The cost reflects the work involved, not a rough estimate. That’s why we ask a few questions first and give you a clear price before any work starts.
Asking for a quote
To make quoting easier, please include:
- Access, such as stairs, a lift or height
- Where the job is, and your postcode
- Pictures of the joints, sent by email
- The rough size of the job
If you are in Kemprow and need external mastic, phone 0345 464 0079 or drop us an email. Tell us what the problem is and where, and you’ll get a clear quote before work begins.
Walls and rooflines in Kemprow
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. With historic houses such as High Elms Manor (about 2.7 miles north-west) nearby, there’s older building stock in the area around Kemprow as well as newer homes. Where a home is older, older walls and rooflines need a sealant that moves with them and suits the material.
If you look after a building such as Fair Field Junior School, movement joints, cladding joints and gutters on larger buildings need the same care as a house’s. Letting a property close to Radlett station? Then failed wall and movement joints let damp in, so they’re worth checking between tenancies.
Kemprow is about 3 miles north of Bushey, in Hertfordshire. For external mastic in and around Kemprow, please phone 0345 464 0079 or email us for a quick quote. We cover Hertfordshire from our Crawley base, Kemprow included. 381 places in Hertfordshire are on our list. For nearby work, see our London page, about 16 miles away.
We cover every part of WD25 for external mastic and the streets around it. Whether your property is on Kemprow and High Cross or anywhere close by, we can help. Neighbouring places we cover for external mastic include Round Bush (1 mile south), Aldenham (1 mile south-west), Radlett (1 mile east), Letchmore Heath (1 mile south) and Patchetts Green (1 mile south-west). Within a short drive, we also cover Watford (3 miles south-west), Hemel Hempstead (7 miles north-west), St Albans (5 miles north), Welwyn Garden City (10 miles north-east), Harpenden (9 miles north) and Hoddesdon (15 miles east).
Landmarks near Kemprow
Locally, jobs take us to homes and businesses close to Garston Park, Three Horseshoes Public House and Queens' School. The nearest railway station is Radlett station, about 1.1 miles east of the centre. A little further out are Radlett and District Museum (1.1 miles east) and Harlequin Centre (2.9 miles south-west). For a walk, there’s Broad Colney Lakes and Verulamium Lake.
When to call us in Kemprow
Buildings move more than people expect. Clay bricks expand slightly over their life, concrete and block shrink, and everything moves with temperature and wet. The sealant in the movement joints takes that strain.
Keep an eye out for any of the following:
- Failed sealant between panels on a façade
- Old sealant gone brittle and cracked
- Failed seals between different materials
- Sealant that has lost its bond to the brick or render
In the older streets around St John, older walls, gutters and the joints where extensions meet them need a flexible sealant.
Comparing quotes
- What the cure time is
- How hidden problems are handled
- Who does the work, and how experienced they are
- Whether they’re fully insured
The process
Our applicators work methodically: protect, prepare, seal, tidy. For most jobs that takes a few hours for a handful of joints, longer for a whole elevation. For a village or hamlet like Kemprow, the journey is planned in advance: tell us about narrow lanes, gates, long drives and where we can park. Everything for the job comes with us, so a second trip is avoided where possible.
- We start by walking round the building and agreeing the joints and the access.
- Every bit of old sealant and any mortar or debris is cut out.
- Joint faces are cleaned back and primed if the sealant needs it.
- We fit closed-cell backing rod to control the depth.
- We apply the sealant, tool it and check the whole run.
Getting ready for the visit
- Let us know if you’ve seen damp or leaks
- Mention if the joints have been sealed before
- Move anything stored near the joints
How to get a quote
Asking for a quote is easy: let us know the job and the location, and roughly how big it is. Photos by email help us understand the job, and we will come back to you with a quote.
Related advice
FAQs for Kemprow
Will you come out to Kemprow?
Yes. Kemprow is within the area we cover, which takes in towns, villages and rural addresses. We work across London and the South East. Let us know about access, parking and anything unusual about getting there when you book.
Is Kemprow in your area for external mastic?
Yes, Kemprow is within the area we cover. Our work covers London and the South East. Just phone 0345 464 0079 or send us an email with a few details of the job, and we will give you a clear quote.
How long should I leave it?
Most sealants are touch-dry well before they’re fully cured. We will give you the cure time for the product we used.
How long does the job take?
Typically it takes a few hours for a handful of joints, longer for a whole elevation. Bigger jobs take longer, and we’ll tell you how long to expect.
Should I point up the gap in my brickwork?
No, not where the gap is a movement joint. Filling it with mortar defeats its purpose and can lead to cracking. We will reseal it with a flexible sealant.
Will you leave a mess?
No. We protect the surfaces around the joints, and we clear up the old sealant and our materials before we leave.
Is the work guaranteed?
Yes. Every job comes with our one-year guarantee.
Do you hold any approvals?
Yes. Mr Mastic is an ARBOMaster approved applicator.
Should I try it myself first?
The biggest DIY mistake is sealing over old sealant. New silicone will not bond to old, so it lifts and traps water and mould underneath. Everything old must be removed first.
Overfilling a joint is a classic DIY mistake. A heavy bead looks messy and copes badly with movement, and getting the depth right matters as much as the look.
Honest limits
We won’t take on work that won’t last, so these are the limits:
- Damp that isn’t coming from the joint
- Subsidence or other structural problems
- Failed render or damaged cladding panels
Not sure which it is? You can phone 0345 464 0079 or email us and we will tell you honestly before you book.
Where we work in Kemprow
- Joints between brick and frames
- Concrete & block
- Render & cladding joints
- Brickwork movement joints
- Copings & trims
- Façade panels
Leave it or put it right?
Resealing a run of joints in one go is usually better than patching one at a time. They’ve weathered the same way and it means sorting access once. Around Kemprow, older homes often have timber in their floors and frames, where water from a failed joint can cause rot if it’s left.
The cost depends on the size of the job, how much old material has to come out and access to the work. We give a clear quote before any work starts.
Why choose Mr Mastic in Kemprow
- We never seal over old sealant
- A choice of colours where the product allows
- Every job guaranteed for a year
- Approved under the ARBOMaster scheme
Take a look at our cost guide and what customers say.