Hertfordshire · England
External & façade joints in How Wood, Hertfordshire
External mastic in How Wood from a team with over 20 years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Rain getting behind render or cladding at a joint
- Moss and dirt in joints with no sealant left
- Joints where the bead has come unstuck
External mastic in How Wood, done properly
Low-level joints can normally be done from the ground. For joints higher up, give us some details of the building and we will confirm what’s needed to reach them safely. We’re often asked to deal with rigid filler in a joint that should flex and hard, crazed mastic that has stopped moving, across joints between brick and frames, concrete & block and render & cladding joints.
Homes around How Wood range from older cottages to newer houses, with walls and rooflines of every type. Older gutters and trims need their joints resealed; newer brick and render need their movement joints kept sound.
You get a 12-month guarantee, the same in How Wood as everywhere else we work.
- Where
- How Wood (AL2)
- Region
- Hertfordshire
- Cover
- One year on every job
- Quote
- A clear quote up front
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
Your questions about external mastic in How Wood
Is How Wood within the area you cover?
Yes, How Wood 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.
Do you work for landlords with property near How Wood station?
Yes, landlords and agents are among the people we work for, and several properties can be quoted together. Just call 0345 464 0079 or send us an email with the address and what needs doing, and we’ll send you a clear quote.
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.
Is there any odour?
That depends on the sealant. Some products have a noticeable smell, others very little, and any smell fades as they cure.
How long before the joint can be used?
It depends on the product and the temperature. Before we leave, we’ll tell you the cure time.
How long does external mastic take?
That depends on how much there is to do, but most jobs take a few hours for a handful of joints, longer for a whole elevation. We will give you a better idea when we quote.
Can you do several jobs on one visit?
Yes, we can. Several rooms, windows or areas can go on one quote.
Will you leave a mess?
No. We protect the surfaces around the joints, and we tidy up before we go.
Work for landlords, hotels and businesses
From a single let to a portfolio, you get the same standard of work: old sealant fully removed, joints prepared properly and a one-year guarantee.
Landlords and letting agents in How Wood can book us as well as householders. Resealing between tenancies is a simple way to keep a property in good order.
How Wood buildings and the weather
Historic houses like High Elms Manor (about 2.2 miles south-west) are a reminder that the area around How Wood has older buildings as well as new. In older buildings, older brick and stone need a sealant that suits them, at the right joint depth. 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.
Rented homes near How Wood station change hands often, and outside joints that have cracked can let damp into a rental, so check them between lets. Schools such as How Wood Primary and Nursery School are buildings too, and larger buildings have long runs of movement joint that eventually need resealing.
How Wood is about 2 miles south-west of St Albans, in Hertfordshire. How Wood gets the same service as everywhere we cover: old sealant removed completely, careful preparation and a 12-month guarantee. How Wood is one of 381 places in Hertfordshire we cover. London is on our list too, around 19 miles away.
Every address in AL2 is covered for external mastic. We cover properties on Ringway Road, Alder Close and How Wood and the roads around them. We also cover Park Street (1 mile north-east), Chiswell Green (1 mile north-west), Frogmore (1 mile east), Bricket Wood (1 mile south-west) and Colney Street (1 mile south-east). Within a short drive, we also cover Watford (4 miles south-west), Hemel Hempstead (5 miles north-west), Stevenage (15 miles north-east), Welwyn Garden City (9 miles north-east), Harpenden (7 miles north) and Hoddesdon (15 miles east).
Around How Wood
Around How Wood, our work takes us to homes and buildings near Marlborough Science Academy and The Falcon pub and the streets around them. There’s a railway station in How Wood itself: How Wood station. Well-known places in the area include Hilfield Castle (4.6 miles south) and Hypocaust Museum (2.1 miles north). The countryside around How Wood includes Broad Colney Lakes and Verulamium Lake.
Nearby places to How Wood
Other services in How Wood
Signs you need external mastic in How Wood
Joints sealed without backing rod, or far too deep, rarely last. If the sealant sticks to the back as well as the sides, it can’t stretch and rips as the joint opens.
The problems people generally mention when they call include:
- Brick movement joints where the sealant has split
- Moss and dirt in joints with no sealant left
- Old sealant gone brittle and cracked
- Joints where the bead has come unstuck
Homes close to Church of the Holy Trinity include some older properties, and an extension built onto an older house moves differently, and the joint between them takes the strain.
What to look for in a quote
- What the cure time is
- Which sealant they’ll use, and why
- What guarantee comes with the work
- What the quote includes, VAT included or not
What affects the cost of external mastic
Every job gets its own quote. This is what makes a difference:
- How much old sealant there is and how hard it is to remove
- The size of the job
- Mould in or behind the old joints
- The product the joint needs
We don’t show prices on the website, because each job is priced on what it involves. For a quick quote, please ring 0345 464 0079 or drop us an email.
Helping us quote
What to tell us when you ask for a quote:
- Photos by email, if that’s easy
- Whether it has been sealed before
- Roughly how big the job is
- How we’d reach the joints
Call for a quick quote, or email us if that is easier. Describe what needs sealing and we’ll talk you through the work.
When something else is needed
We will not take on work that will not last, so here’s what sealant cannot put right:
- Damp from another source, such as a leaking gutter or a bridged damp-proof course
- Walls that need new movement joints cut into them
- Cracks in the bricks or render themselves, away from the joints
If in doubt, call 0345 464 0079 or drop us an email and we’ll say what we think.
What we seal
- Copings & trims
- Joints between brick and frames
- Render & cladding joints
- Concrete & block
- Façade panels
- Brickwork movement joints
DIY versus a professional finish
Some sealant jobs are within reach of a careful DIYer, such as a straightforward joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
If you do try it yourself, take your time over the preparation: remove every trace of old sealant, clean and dry the joint, and follow the product’s cure time. If it fails, we can still redo it.
The process
We work through the job in order: protection first, then preparation, sealing and a tidy-up. Typically it takes a few hours for a handful of joints, longer for a whole elevation. A visit to How Wood is planned like any other: the time, the access and where to park are agreed in advance. Outdoor jobs depend on a dry day, since sealant needs a dry surface.
- We start by checking each joint, agreeing the ones to redo and how we’ll reach them.
- The old mastic and anything lodged in the joint is removed.
- We clean both faces of the joint and prime them where the product calls for it.
- Closed-cell backing rod is fitted to set the depth and stop three-sided bonding.
- The new sealant, chosen to suit the brick or render, is applied and tooled to a neat finish.
Preparing for the visit
- Tell us about any water getting in
- Let us know about earlier repairs to the joints
- Tell us about access, such as stairs, a lift or high-level joints
Getting a quote
There’s no standard price list, because every job is different. Instead, we give you a clear quote for your job. To get started, call 0345 464 0079 or send us an email.
Related advice
Why it’s worth doing now in How Wood
A low-modulus sealant is chosen because it moves without pulling hard at the edges. That matters on brick, render and concrete, which can be weaker at the face. Too stiff a sealant can pull at the edges and break them. In a smaller place like How Wood, wherever a wall is exposed, a failed outside joint is a real source of damp. Indoors, a failed seal lets water into floors and panels as it would anywhere.
The cost reflects the work involved, not guesswork. That’s why we ask about the job first and agree the price before starting.
Why How Wood customers choose us
- Any old sealant cut out fully, not covered over
- Tidy, careful work
- One-year guarantee on every job
- Experience in homes, commercial sites and hotels
Read our cost guide and our reviews.