What Should Builders Know Before Using Reclaimed Materials?

Quick answer: Before specifying reclaimed materials, builders should confirm the material is fit for its intended use under Building Regulations (Approved Document 7), find out where it came from and how it was used before, check frost resistance and condition for the exposure it will face, secure the full quantity plus 10 to 15% extra from a single batch, match size and mortar to the existing building, and budget for sorting, cleaning and extra labour. Reclaimed materials rarely come with a manufacturer’s declared performance, so the checks fall on you and your supplier.

Reclaimed materials are brilliant. They match old buildings in a way new products never quite manage. They save carbon. And on a period renovation, they’re often the difference between a repair that disappears and one that sticks out for the next 50 years.

But specifying them isn’t the same as ordering from a builders’ merchant catalogue.

Think of it like buying a used van versus a new one. The new van comes with a spec sheet, a warranty and a known history (none). The used van might be the better buy, but you’d want to know the mileage, what it’s been carrying and whether it’s spent ten winters parked by the sea. Reclaimed bricks, slates and timber are the same. The quality is often superb. You just need to ask the right questions first.

Here’s what we tell tradespeople at our Stoke yard before they put reclaimed materials on a spec.

Why specifying reclaimed is different from specifying new

New bricks made in the UK are produced to BS EN 771-1 and come with a declaration of performance. You get stated figures for compressive strength, water absorption, frost resistance and soluble salt content.

Reclaimed bricks don’t arrive with that paperwork. Neither do most reclaimed slates, tiles or flags.

That doesn’t mean they’re worse. Plenty of Victorian bricks have already survived 120 years of British weather, which is a better durability test than anything in a lab. It just means the responsibility for checking suitability shifts towards you, your client and your supplier.

If you’re still weighing up whether reclaimed is right for the job at all, our guide to reclaimed bricks vs new bricks covers the pros and cons in more detail.

1. Fit for purpose is the legal test

A lot of builders assume reclaimed materials are a grey area with building control. They’re not.

What Building Regulations actually say

The Building Regulations don’t stop you using reclaimed materials. What matters is Regulation 7 on materials and workmanship, supported by Approved Document 7. The test is simple: is the material adequate and appropriate for the job it’s doing?

Approved Document 7 accepts several ways to show that, including tests or calculations and experience, such as proven performance in an existing building. A reclaimed slate that kept a roof dry for a century is, in effect, bringing its own evidence.

Where other parts of the Regs still bite

The material being sound doesn’t automatically make the use compliant. A few common traps:

Structural timber used for anything load-bearing should be strength graded, because age, old notches and previous loading affect strength in ways you can’t always see.
Reclaimed windows and doors going into an extension or new opening may not meet thermal performance requirements under Approved Document L.
Doors in certain positions may need a specific fire rating.
Bricks for external walls need adequate frost resistance for the exposure, not just the right colour.

Talk to building control and conservation early

Raise reclaimed materials at the start, not when the inspector turns up. On listed buildings or in conservation areas, speak to the conservation officer too. They’ll often actively want reclaimed materials, but they may want to see samples first.

2. Know where the material came from

Provenance is the single most useful thing you can ask about. Where a material lived its first life tells you a lot about how it will behave in its second.

Internal bricks and external bricks get mixed up

This is the big one. When a building is demolished, the soft internal bricks and the hard-wearing external facing bricks can end up in the same pile. An internal common that never saw rain might look fine on a pallet, then spall and crumble after its first hard winter on a gable end.

A good reclamation yard sorts for this. Ask the question anyway, and inspect a sample for signs of the old face, weathering and density.

Salts and contamination

Reclaimed bricks can carry soluble salts from groundwater, old mortar or the previous site. That can show up as efflorescence or, worse, sulphate attack on cement mortars. Bricks from industrial or agricultural buildings may also carry residues from decades of use.

Where the history is unknown, take a cautious approach to mortar choice and detailing, and avoid using questionable stock in the wettest parts of the building.

3. Secure the full quantity before you commit

Here’s a real-world scenario we see all the time.

A builder is putting a rear extension on a Victorian terrace. The client loves a particular reclaimed red. The builder orders 3,000 bricks, gets two-thirds of the way up the walls and realises they need another 600. By then, that batch has gone. The next lot is a similar red from a different demolition, slightly darker, slightly smaller. Now there’s a visible line across the back of the house.

Reclaimed stock only exists in the quantity that came out of one building. Once it’s gone, it’s gone.

How to avoid it

Calculate carefully, then add a margin. As a rule of thumb, allow around 10 to 15% extra for reclaimed bricks and tiles to cover cutting, breakages and rejects, compared with roughly 5% for new.
Buy or reserve the whole job from one batch, ideally in one go.
Blend from every pallet as you lay, so natural variation spreads evenly rather than appearing in bands.
Sort before you start. Pull out anything cracked, spalled or badly chipped on day one, not halfway up a wall.

Our paving calculator and guide to how many roof slates you need per m² are useful starting points for quantities.

4. Match the building, not just the colour

Colour gets all the attention. Size and mortar matter just as much.

Check the dimensions

Older imperial bricks are often a little larger or deeper than modern 65mm bricks. Mix the two and your coursing won’t line up, which is far more noticeable than a slight colour difference. Take a tape measure to the existing wall and to the sample. Our post on common sizes and colours of reclaimed bricks explains what to look for.

The same goes for roofing. Reclaimed slates and clay tiles come in many sizes and thicknesses, and the gauge, headlap and batten spacing all need to suit what you’re actually using.

Get the mortar right

Most pre-1919 buildings were built with lime mortar. Older bricks are often softer than modern ones, and the mortar should always be weaker than the brick so it takes the movement and moisture, not the brick face.

Pair soft reclaimed bricks with a hard cement mortar, and you can trap moisture in the brick, leading to frost damage and spalling. For most period work, a lime or lime-rich mortar is the safer spec.

Expect some cleaning

Bricks may still have old mortar on them. Budget time for cleaning or specify cleaned stock. See our guide on how to clean and prepare reclaimed bricks before use.

5. Material-by-material checks

Every reclaimed material has its own quirks. Here’s what to look at for the products we’re asked about most.

Reclaimed bricks

Confirm they were external-facing bricks if they’re going on an external wall.
Look for spalling, deep cracks and crumbling arrises.
Check the size against the existing brickwork.
For anything beyond domestic low-rise, or anywhere structurally demanding, get representative samples tested for strength and frost resistance.

Using them on a newer property? Read are reclaimed bricks suitable for modern homes and extensions?

Reclaimed roof slates and clay tiles

Tap slates and listen. A good slate rings; a dull thud can mean hidden delamination.
Look for flaking, cracking and soft edges around the nail holes.
Check thickness consistency, especially if you’re mixing with the existing roof.
Don’t forget the fittings. Matching ridge tiles, hips, valleys and tile-and-half are often harder to find than the main tiles.

If you’re patching an existing roof, a common approach is to use reclaimed tiles on the visible front elevation and put any shortfall on the rear. Our posts on sustainable roofing for restoration projects and how to repair a roof go into more detail.

Reclaimed stone paving and York stone

Reclaimed flags vary in thickness, so bedding depths will vary too. Allow for that in your labour.
Check for laminations, cracks and old oil staining.
Consider the use. Thin flags that are perfect for a patio may not be right for a driveway.

We’ve covered this in: Is reclaimed stone paving frost-resistant and weatherproof?, can reclaimed paving be used for driveways? and what to look for when buying reclaimed stone paving. For the most popular option, see what is reclaimed York stone?

Reclaimed railway sleepers

This is where the rules are strictest, and where a lot of people get caught out.

Many reclaimed sleepers were treated with creosote. Since 2003, creosote-treated timber can’t be used inside buildings, in toys or play areas, for garden furniture, in places where there’s a risk of frequent skin contact, or where it could touch food or animal feed. In hot weather, older sleepers can also ooze tar.

In practice:

Reclaimed suit retaining walls, landscaping edges, steps in low-contact areas and driveway borders.
New are the better spec for vegetable beds, benches, seating walls, children’s areas and anything indoors.

We stock both new railway sleepers and reclaimed railway sleepers, so you can choose by use rather than compromise.

Reclaimed scaffold boards

Reclaimed scaffold boards are popular for shelving, cladding, furniture, raised beds and rustic interiors. They are not for use as scaffold platforms. For anything that needs to carry people as a working platform, specify new boards made to the correct standard.

When using reclaimed boards, check for:

Old nails, staples and metal banding
Splits and rot, especially at the ends
Moisture content if they’re going indoors, as damp boards will shrink and twist once the heating goes on

See our reclaimed scaffold boards and new scaffold boards.

Reclaimed timber and flooring

Check for woodworm, rot, hidden metal and moisture. Any structural use needs grading. For floors, read is reclaimed timber suitable for indoor flooring?

6. Budget for the hidden costs

Reclaimed materials can be cheaper than new. Sometimes they’re more expensive, especially rare handmade bricks or large runs of matching York stone. Either way, the material price isn’t the whole story.

Factor in:

Sorting and cleaning time on site
Higher wastage than new stock
Slower laying, because irregular sizes take more care
Testing, if the job or the client needs it (Gardiners don’t test themselves, so this would have to be done yourself)
Delivery, especially for heavy items over long distances

Price it properly at the quote stage and the client won’t be surprised later. Our guide to how much reclaimed building materials cost in the UK gives typical ranges.

7. Be clear about warranties and risk

New products come with manufacturer guarantees. Reclaimed products usually don’t, at least not to the same level.

So protect yourself:

Agree the material choice in writing with your client.
Explain that natural variation, chips and patina are part of the look.
Keep photos and delivery notes.
Build a sample panel and get it signed off before the main work starts.

That sample panel is worth its weight in gold. It settles colour, texture, bond and mortar in one go, and it stops “that’s not what I expected” conversations later.

8. Know when new is the better call

Reclaimed isn’t always the answer, and a good supplier will tell you so.

For the most exposed parts of a building, such as parapets, chimneys, copings and anything below DPC, the uncertainty around older stock can outweigh the benefits. In those spots, a new product with declared performance, chosen to blend with the reclaimed work, is often the smarter spec.

This hybrid approach is common on good jobs. Reclaimed where it’s seen and where it performs well. New where the conditions are harshest or the rules are tightest. Because we sell both new and reclaimed bricks, roofing, sleepers, scaffold boards and paving, we can help you mix the two without it showing.

There’s also a sustainability angle to remember. Reclaimed materials have very low embodied carbon, but long delivery distances eat into that benefit. Sourcing as locally as you can helps. Read more on how are reclaimed materials more sustainable than new ones? and sustainable construction using reclaimed materials.

A quick pre-specification checklist

Before reclaimed materials go on your spec, tick these off:

Is the material fit for this specific use and exposure?
Do you know where it came from and how it was used?
Have you checked the condition on a representative sample?
Is the full quantity, plus 10 to 15% extra, available from one batch?
Do the sizes match the existing work?
Is the mortar or fixing method compatible?
Have building control or the conservation officer been consulted where needed?
Are cleaning, wastage and extra labour priced in?
Has the client signed off a sample panel?
Would a new product be safer for any high-exposure details?

See it before you specify it

Photos only tell you so much. Colour, texture and condition are much easier to judge in person, which is why many of our trade customers visit the yard before they commit.

You’ll find us at Grove Road Industrial Estate, Fenton, Stoke-on-Trent, ST4 4LG. Bring a sample of the existing brick or tile and we’ll help you find the closest match. Can’t get to Stoke? We deliver reclaimed materials nationwide, and we handle trade and bulk orders for larger jobs. Call us on 01782 334 532 or get in touch.

Summary

Specifying reclaimed materials is less about the product and more about the questions you ask. Check its fit for purpose, know its history, buy enough from one batch, match size and mortar to the building, and price in the extra handling. Use new materials where exposure or regulations make reclaimed a risk. Do that, and reclaimed bricks, slates, paving and timber will give your project character that lasts for generations.

Frequently asked questions

Do reclaimed building materials meet UK Building Regulations?

They can. The Building Regulations don’t prohibit reclaimed materials, provided they’re fit for their intended purpose. Approved Document 7 allows suitability to be shown through tests, calculations or past performance in an existing building. Other parts of the Regs, such as thermal performance or fire safety, still apply to the finished work.

How many extra reclaimed bricks should I order?

As a general rule of thumb, order around 10 to 15% more than your calculated quantity. Reclaimed bricks have more rejects and breakages than new ones, and a matching batch may not be available later. It’s far cheaper to have a few spare than to hunt for a match halfway through a wall.

Can I use reclaimed bricks for a chimney or below the damp-proof course?

Only with care. Chimneys, parapets and below-DPC brickwork face the harshest conditions, so the bricks need proven frost resistance and low soluble salt content. Unless you know the bricks came from a similar exposed position, a tested reclaimed brick or a matching new brick is usually the safer spec for these areas.

Are reclaimed railway sleepers safe for raised vegetable beds?

Creosote-treated reclaimed sleepers aren’t suitable for growing food, garden seating or anywhere with frequent skin contact. For vegetable beds and seating, specify new untreated or pressure-treated sleepers instead. Reclaimed sleepers are better suited to retaining walls, edging and general landscaping.

Can I mix reclaimed and new roof tiles on the same roof?

Yes, but plan it. New tiles will look noticeably cleaner for years, so many roofers put reclaimed tiles on the front or most visible slope and use new ones on the rear. The tiles must also share the same size, profile and gauge so they lap correctly and keep the roof weathertight.

What Should Builders Know Before Specifying Reclaimed Materials?