Shepherd and Sons Contracting ltd
FAQ
Answers based on experience
ASK THE EXPERTS
The Questions We Hear Most
From how our sealants behave to how quickly a surface can reopen to traffic, this page answers the questions we are asked most. You will find practical guidance on joint sealing, sealants and surface repair, alongside answers about who we are and how we work. As a third-generation, Kent-based specialist surfacing contractor, we have drawn these answers from more than 40 years of work across aviation, highway, ports and public projects.
How long has Shepherd and Sons been operating?
Our surfacing pedigree runs back more than 40 years. The lineage began with Shaw-Seal Ltd, founded in 1966 by Alan Shepherd, which held the chairmanship of the Extruded Sealant Association in 1989 and worked across the UK’s seven largest airports. The current business, Shepherd and Sons Contracting Ltd, was launched in 2023 by Richard, Jordan and Sasha Shepherd as the third generation of the family to do this work. You can read the full account on our history page.
Are you accredited?
Yes. We are members of the Extruded Sealant Association and hold both SafeContractor and CHAS accreditation. We have also been the sole contractor for BAA PLC since 2008, working within the BAA pavement team framework. In our experience, that combination matters more to clients than any single certificate, because airfield and highway clients are auditing not just whether you can do the work but whether your safety and quality systems will survive their own compliance checks.
What sectors do you work in?
We work across four: aviation, highways, ports and public infrastructure. Aviation is where our deepest experience sits. We have delivered work at all seven BAA airports under the pavement team framework, assisted on the Heathrow Terminal 5 runway in 2005, carried out the A380 Code F conversion work in 2007, and completed roughly 66,000 metres of saw cutting on Terminal 2 in 2012. That airside track record is something a newer contractor cannot reproduce, because it only comes from decades of working live, secure airfield environments.
What is joint sealing and why does it matter?
Joint sealing is the application of sealant into pavement joints, cracks and chases to manage the movement of concrete and asphalt slabs. A properly sealed joint lets slabs expand and contract without cracking, and keeps out water, grit and chemical contaminants. From working with clients across airfields and highways, we have found that the cost of resealing on a planned cycle is consistently lower than the cost of letting water ingress reach the sub-base, where the repair becomes structural rather than a surface job. Our full approach is set out on our joint sealing page.
What is the difference between hot-applied and cold-applied sealants?
Hot-applied sealants, such as N1 and N2 to BS EN 14188-1, are melted and pumped into the slot, and are typically used on highways, car parks and airfields where fast curing is needed. Cold-applied sealants, such as fuel-resistant polysulfides to BS EN 14188-2, are mixed and poured, and are chosen for areas exposed to fuel and chemical spillage. In our experience, a cold-applied fuel-resistant sealant works better than a standard hot-applied product in aircraft fuelling areas and oil terminals because it resists kerosene, petrol, glycols and de-icing salts that would degrade a non-resistant seal over time.
What is Thioflex 555 and when do you use it?
Yes. We are members of the Extruded Sealant Association and hold both SafeContractor and CHAS accreditation. We have also been the sole contractor for BAA PLC since 2008, working within the BAA pavement team framework. In our experience, that combination matters more to clients than any single certificate, because airfield and highway clients are auditing not just whether you can do the work but whether your safety and quality systems will survive their own compliance checks.
Can Thioflex 555 be used on asphalt joints?
No. Thioflex 555 is specified for concrete substrates, and we do not use it on asphalt-to-asphalt joints. It is not compatible with bituminous surfaces and does not meet airport specification in that application, so using it there would carry an unacceptable runway risk. Where a joint runs between asphalt surfaces, we select a product designed and specified for that substrate instead. We will always confirm the substrate before recommending a sealant.
How soon can a surface reopen after joint sealing?
With the machine grade of Thioflex 555, return to service is around 30 minutes, which is the figure we plan our airside works around. That rapid turnaround is the main reason we favour the machine grade on live airfields. In our experience, machine-applied Thioflex 555 works better than hand grade on operational runways and taxiways because the faster return to service lets us hand sections back inside tight overnight possession windows, where the hand grade’s longer cure simply would not fit the closure.
How do you prepare a joint before sealing?
Preparation is where seal life is won or lost. Following the ESA Code of Practice and the manufacturer’s data sheet, the joint slot must be dry, sound, clean, and free from frost and dust before any sealant goes in. We remove sawing slurry before it hardens, roughen smooth slot faces so the primer and sealant can key in, and blow the slot out with oil-free compressed air. On concrete, we prime the faces where the manufacturer requires it, and we keep the primed slot protected from weather and contamination until sealing. We have found that skipping the roughening and cleaning stage is the single most common reason a previously sealed joint has failed early when we are called in to reseal it.
Do you work on live airfields and out of hours?
Yes. We operate round the clock and routinely work within airfield possessions, where access is granted only for a few overnight hours before the surface must be handed back for the first flights. Our airside experience, our accreditations and our fast-return sealing approach are all built around working safely inside those windows.
What is overbanding and how is it different from joint sealing?
Overbanding applies a band of hot material over the surface of a crack or joint to seal it from above, rather than filling a cut slot. Joint sealing reinstates the seal within a properly formed slot. Overbanding is a quicker, surface-level treatment suited to certain cracks, while joint sealing is the fuller solution where the joint itself needs reforming. We will recommend the right one for the defect rather than defaulting to whichever is faster.
What do you need to provide an accurate quote?
The detail we need varies by sector, so the more you can tell us up front, the more accurate the price. The most useful information is the site location, the surface type (concrete or asphalt), the scope and approximate quantity of work, and the access conditions, including whether the area is live and whether works need to run overnight. Because access and substrate drive the method as much as the area does, every price we give is based on the actual conditions on site rather than a templated rate.
Shepherd and Sons Contracting ltd
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