Hertfordshire · England
Gustard Wood External Mastic
Our applicators work in Gustard Wood on sealing brickwork movement joints, render, cladding and façade joints. Old material cut out, joints cleaned and sealed neatly and a one-year guarantee.
- Movement joints with cracked, split or missing sealant
- Sealant pulling away from one side of the joint
- Rain getting behind render or cladding at a joint
What happens on the day
When we arrive, we start by going over the job with you, so you know exactly what we are doing. Surfaces next to the work are protected before any work begins. Most jobs take a few hours to a few days, depending on the length of joint and the access. In a small place like Gustard Wood, access is generally the main thing to plan. For outside work, also let us know about exposed walls and any outbuildings involved.
- 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.
- The faces are brushed clean and primed where the product requires it.
- We fit closed-cell backing rod to control the depth.
- The exterior sealant is applied, tooled and checked along its length.
Before we arrive
- For business premises, tell us about site rules or sign-in
- Clear items away from the joints we are working on
- Keep pets and children clear of the area while we work
Getting a quote
We do not publish a price list. Instead, we give you a clear quote for your job. To get started, ring 0345 464 0079 or email us.
Related advice
External mastic in Gustard Wood
Joints between dissimilar materials, like brick against render or concrete against a steel frame, see movement from both sides. A flexible sealant bridges the two where mortar or filler would crack. We are often asked to deal with rigid filler in a joint that should flex and old sealant gone brittle and cracked, across concrete & block, copings & trims and brickwork movement joints.
Somewhere as small as Gustard Wood, homes and farm buildings often face open ground, where walls and rooflines take the weather head on. Joints on those walls need a sealant that moves with the building and stays in place.
You are covered for a year from the day we finish. If anything is not right with it, call 0345 464 0079 or send us an email.
- Where
- Gustard Wood (AL4)
- Region
- Hertfordshire
- Cover
- One year on every job
- Quotes
- A clear price before we start
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
When something else is needed
Some problems need a builder, plumber or other trade rather than us:
- Cracked brickwork or render that needs a builder or plasterer
- Damp from another source, such as a leaking gutter or a bridged damp-proof course
- Loose or hollow render, which needs re-rendering
If in doubt, call 0345 464 0079 or email us and we’ll say what we think.
Where we work in Gustard Wood
- Brickwork movement joints
- Concrete & block
- Façade panels
- Render & cladding joints
- Joints between brick and frames
- Copings & trims
Should I try it myself first?
Not every job suits DIY: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.
What a professional job adds is preparation and the right product. Joints are cleaned back to sound surfaces and dried, and the sealant is matched to the joint and its conditions, and the work is guaranteed for a year.
Looking after it afterwards
So the new joints stay in good condition:
- Clear growth from the base of walls and joints
- Avoid pressure-washing directly into sealant joints
- Deal with leaking gutters that soak the joints below
- Make sure movement joints aren’t pointed over
Give the sealant the cure time we tell you before anything rubs against it. Most exterior sealants skin fast but take longer to cure right through.
Gaps, plants or missing sealant in a joint are worth getting looked at. Early work is quicker and leaves a better finish.
Walls and rooflines in Gustard Wood
With historic houses such as Shaw's Corner (about 1.2 miles north-east) nearby, there’s older building stock in the area around Gustard Wood as well as newer homes. Where a home is older, older brick and stone need a sealant that suits them, at the right joint depth. London and the South East are among the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
For site and facilities teams at buildings such as St Helen's Church of England Primary School, movement joints, cladding joints and gutters on larger buildings need the same care as a house’s. In the older streets around St Peter, older walls, gutters and the joints where extensions meet them need a flexible sealant. Letting a property close to Harpenden station? Then outside joints that have cracked can let damp into a rental, so check them between lets.
Gustard Wood is about 3 miles east of Harpenden, in Hertfordshire. If you need external mastic in Gustard Wood, it’s easy to get a quote: please call 0345 464 0079 or send us an email. We cover Hertfordshire from our Crawley base. Our Hertfordshire coverage runs to 381 places, and Gustard Wood is one of them. You can also see our page for London, roughly 24 miles from Gustard Wood.
Every address in AL4 is covered for external mastic, from the main roads to the quietest streets. Neighbouring places we cover for external mastic include Wheathampstead (1 mile south), Ayot St Lawrence (1 mile north-east), Kimpton (2 miles north), Ayot St Peter (2 miles east) and Codicote Bottom (2 miles north-east). Larger places within reach include Watford (12 miles south), Hemel Hempstead (9 miles south-west), Stevenage (7 miles north-east), St Albans (5 miles south), Welwyn Garden City (5 miles south-east) and Harpenden (3 miles west).
What’s near Gustard Wood
Typical jobs here are in homes near Sir John Lawes School and The Old Plough Public House and the streets around them. For rail, the closest station is Harpenden station, about 2.7 miles west of the centre. Well-known places in the area include St Albans City Hospital (5.1 miles south-west) and Harpenden Museum (2.9 miles west). For a walk, there’s Wheathampstead Local Nature Reserve.
Towns and villages near Gustard Wood
Also in Gustard Wood
How we quote for external mastic
Some jobs are bigger than they look, and some smaller. What affects the quote:
- Access and height
- Whether old sealant or filler has to be cut out
- The number of rooms or windows
- The amount of work
Doing several joints on one visit is normally more efficient than separate visits, so it’s worth mentioning everything you’d like done. You’ll get one clear quote for the whole job.
What we need to know
There’s no need for technical detail. Just tell us:
- How we’d reach the joints
- Pictures of the joints, sent by email
- The rough size of the job
- Whether it has been sealed before
If you are in Gustard Wood and need external mastic, call 0345 464 0079 or drop us an email. Tell us what the problem is and where, and we’ll agree the price before any work begins.
Work for landlords, hotels and businesses
A neglected joint can let water reach the structure, which matters even more when someone else lives there. Keeping joints in good order is simple maintenance that we can handle for you.
We regularly work with letting and managing agents. Tell us the address, the job and how access works.
Gustard Wood questions
Is Gustard Wood within the area you cover?
Yes, Gustard Wood is covered. Our work covers London and the South East, and smaller places are part of that. The journey is planned ahead, so it helps to know about access.
Do you cover Gustard Wood for external mastic?
Yes, Gustard Wood is within the area we cover. We work across London and the South East. Just phone 0345 464 0079 or email us with a few details of the job, and we will give you a clear quote.
Can you seal joints between two different materials?
Yes. The old joint is removed, both surfaces cleaned and primed where needed, and a flexible sealant applied. The colour is chosen to suit.
How long does external mastic last?
That varies with the weather the wall faces, how much it moves and the sealant used. Treat it as a maintenance item and look at it yearly and renew it when it starts to fail.
Are you insured?
Yes. We’re fully insured, with over 20 years’ experience in sealant work.
Are you ARBOMaster approved?
Yes. We hold ARBOMaster approved applicator status.
What sealant do you use?
It depends on the joint: anti-fungal sanitary silicone in wet areas, and other sealants where joints move or face the weather. We use products from Arbo and Everbuild.
How long does external mastic take?
That depends on the amount of work, but as a guide it takes anything from a few hours to several days, depending on the building. We will tell you when we quote.
How the job changes by surface
Cladding and façade panels
Metal and composite panels move a lot with temperature, so the joint sealant has to cope with frequent movement. We choose the product to suit.
Render joints
Cracks along render joints let water in behind the coat. A sound joint keeps the render dry behind and helps it last.