Hampshire · England
Knightwood External Mastic
Sealing brickwork movement joints, render, cladding and façade joints in Knightwood, with a 12-month guarantee on every job. Ask us for a quote.
- Joints pointed up with cement by mistake
- Hard, crazed mastic that has stopped moving
- Damp patches traced to an open external joint
Different surfaces, different methods
Copings and trims
A failed coping joint lets water into the top of the wall. Sealing them early saves the wall below.
Concrete and blockwork
Concrete faces can be dusty and porous, so cleaning and priming matter. We prime where the sealant needs it before the bead.
About our external mastic in Knightwood
Joints in render and cladding are easy to overlook until a damp patch appears. We look over the joints, agree the ones to renew and reseal with a flexible, weatherproof product in a colour to suit. If you have failed seals between different materials and leaking joints around cladding and façade panels, we can help, whatever the surface.
In a smaller place like Knightwood, some homes face open ground, and walls and rooflines facing the weather take the worst of it. Joints on those sides are generally the first to go.
Every job is covered by our one-year guarantee.
- Location
- Knightwood (SO53, SO52)
- Wider area
- Hampshire
- Guarantee
- 12 months on all our work
- Price
- A clear quote up front
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
External mastic in Knightwood: local notes
Historic houses like South Stoneham House (about 3.7 miles south) are a reminder that the area around Knightwood has older buildings as well as new. Where a home is older, older walls and rooflines need a sealant that moves with them and suits the material. The South East is one of the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
Letting a property close to Chandlers Ford station? Then outside joints that have cracked can let damp into a rental, so check them between lets. For an older house near a landmark such as St Francis, an extension built onto an older house moves differently, and the joint between them takes the strain.
Knightwood is about 1 mile west of Chandler's Ford, in Hampshire. For external mastic in and around Knightwood, it’s easy to get a quote: please phone 0345 464 0079 or email us. We’re based in Crawley and cover Hampshire. Knightwood is one of 683 towns and villages in Hampshire we cover.
Jobs for external mastic in SO53 and SO52 is quoted and booked the same way as anywhere else. Local streets include Foyle Road, Harvest Road and Flexford Road, all of which we cover. Nearby, we also carry out external mastic in Chilworth Old Village (2 miles south-west), Chilworth (2 miles south), North Baddesley (2 miles west), Toothill (3 miles south-west) and Bassett (3 miles south). Further out, we also cover Winchester (6 miles north-east), Eastleigh (3 miles south-east), Fareham (13 miles south-east), Totton (7 miles south-west), Hedge End (7 miles south-east) and Romsey (4 miles west).
Near you in Knightwood
In Knightwood, that means homes and buildings near Toynbee School, among other places. The nearest railway station is Chandlers Ford station, about 0.8 miles south-east of the centre. Other landmarks nearby include Romsey Community Hospital (3.5 miles west) and Eastleigh Museum (2.5 miles south-east). Open spaces near Knightwood include Flexford Nature Reserve.
DIY versus a professional finish
The difference is mostly in the preparation and the product. We take joints back to clean, dry surfaces, and the sealant is matched to the joint and its conditions, and the work is guaranteed for a year.
Overfilling a joint is a classic DIY mistake. A thick, smeared bead looks untidy and does not move well, and getting the depth right matters as much as the look.
What affects the cost of external mastic
Every job gets its own quote. These are the things that affect it:
- How much old sealant there is and how hard it is to remove
- How much there is to do
- How easy the joints are to reach
- Which sealant suits the joint
Instead of a standard rate, we price the job in front of us: how many joints, what’s in them now and how we reach them. You’ll know the price before we begin.
What to tell us for a quote
There’s no need for technical detail. Just tell us:
- The problem you’ve noticed
- If someone has resealed it before
- The rough size of the job
- A few pictures by email, if you can
Getting a quote is simple: tell us what needs doing and where. A few pictures by email make the job easier to understand.
What happens on the day
We bring everything the job needs with us. Once we’ve agreed what’s being done, we protect the area and start. Most jobs take a few hours for a handful of joints, longer for a whole elevation. In a smaller place like Knightwood, parking is seldom the issue; lanes, gates and long drives are worth mentioning. For outside work, side access and the height of the joints help us plan.
- First we look over the joints with you, agree which to renew and talk through access.
- We cut out the failed sealant and rake out any dirt or growth.
- Both sides are cleaned back to sound material and primed if needed.
- We push in closed-cell backing rod so the sealant is the right depth and bonds to the sides only.
- We gun in a flexible exterior sealant in a colour that suits the wall and tool it neatly.
How to prepare
- Mention any leaks or damp you’ve noticed
- Mention any parking rules near the property
- Try not to wet indoor joints just before the visit
How to get a quote
Want a quote for external mastic? Please call 0345 464 0079 or email us with a few details. We will explain what we’d do and send you a clear quote before any work starts.
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What sealant work can’t fix
Sealant isn’t the answer to every problem, and we’d rather say so up front. It won’t solve:
- Cracked brickwork or render that needs a builder or plasterer
- Structural movement, which needs a surveyor or engineer
- Render that is blown, hollow or coming away
If in doubt, phone 0345 464 0079 or email us and we’ll say what we think before you book.
Joints and surfaces we work on
- Joints between brick and frames
- Brickwork movement joints
- Render & cladding joints
- Façade panels
- Concrete & block
- Copings & trims
Do you need external mastic in Knightwood?
Every building moves. 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.
People normally contact us when they notice one of these:
- Old sealant gone brittle and cracked
- Sealant pulling away from one side of the joint
- Water getting into walls through failed joints
- Leaking joints around cladding and façade panels
Schools such as Knightwood Primary School are buildings too, and its movement joints, gutters and trims need looking after like any other building’s.
What your quote should include
- When the joint can take water or movement
- What happens if the job turns out different
- Is VAT in the price?
- Who turns up on the day
Knightwood questions
Do you cover Knightwood for external mastic?
Yes. We work across London and the South East, and Knightwood is part of that. Just call 0345 464 0079 or send us an email with a few details of the job, and we will give you a clear quote.
I let a flat near Chandlers Ford station. Can you help?
Yes. We work for letting agents and landlords as well as homeowners, and several properties can go on one quote. You can call 0345 464 0079 or send us an email with the details for a clear quote.
Is there any odour?
Sometimes, a little. Any smell clears as the sealant cures, and ventilation helps.
Are you insured?
Yes. We are fully insured for every job we do.
How do you reach high-level joints?
It depends on the height and the site. Low-level joints are straightforward; for higher work, tell us about the building and we will confirm what’s needed.
Is the work guaranteed?
Yes: twelve months. If anything is not right with the work within the year, let us know and we’ll sort it.
Can you match the colour of my brickwork?
There’s a good range of exterior colours, including greys, browns, whites and stone tones. We choose the closest to your brick or render.
Do you hold any approvals?
Yes. We’re an ARBOMaster approved applicator, the approved applicator scheme for Arbo sealants.
Looking after it afterwards
To keep the joints looking good and working properly:
- Look over the joints every year, ideally after winter
- Avoid pressure-washing directly into sealant joints
- Point out the joints to other trades
- Have failed joints looked at early
Avoid pressure-washing straight into the joints. High-pressure water can lift the edges.
A joint that has stopped moving pushes the movement elsewhere, normally as cracking in the brickwork or render nearby. Catch it early and you reduce the risk.