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If you are considering an extension think about matching the roof tiles, bricks and stone to your original build. It may be that you want a modern extension to complement your existing structure, but if you want a seamless look, matching these aspects to your original structure may need some planning.

We found this useful article in Homebuilding and Renovation on what you need to consider if you want to match the roof tiles, bricks and stones to your original structure.

Nothing ruins a house more than a badly matched extension, but with a little research, your new space can look as though it has been there forever. There are several cardinal sins when it comes to extension design, but within this article the focus is on how to source, alter and use materials in order to get your extension to blend seamlessly with what is already there.

Your main focus when striving for a matching extension should be the materials you use for its construction – namely the bricks and roof covering – but do not overlook the details that hold them together.

Matching Bricks

Matching the new bricks to the old is where it all too often goes horribly wrong for many extenders.

There are several factors to consider when choosing a brick to match your existing:

• Colour
• Size
• Texture
• Bond

To find a match, you have a couple of options.

Reclaimed Bricks

Salvage yards too usually have a huge stock of bricks and will be happy to provide samples. On the plus side, you might be able to source an exact match, they will have aged naturally, and will carry with them plenty of character — plus they can be sourced in imperial sizes to match the period originals.

There is the sustainable aspect of using reclaimed materials to bear in mind too, as they have minimal impact on the environment. It is also an easy way to keep the planners happy in cases where the use of sensitive materials has been specified.

If you opt for reclaimed bricks, be sure to buy from a reputable source and check the batch you are buying thoroughly. Also, make a note of the lot number you ordered before delivery, as it is not unknown for the wrong bricks to be delivered, leaving you with bricks that are a close but not exact match. Wastage with reclaims can also be an issue. In some cases up to 30 per cent are unusable, whereas there is little or no wastage with new bricks.

New Bricks

If reclaimed is not for you, then you can still get an exact match as many manufacturers offer bespoke brick matching. Most brick matching services are free and rely on a picture or sample of the old brick, giving you either exact matches or a good alternative. If it is the sustainable aspect that is important to you, consider that the majority of newly made bricks have an expected life of at least 150 years, meaning that walls built with new bricks get an A+ rating by BRE.

Then there is the quality of the reclaimed bricks. “It is unlikely that reclaimed bricks have been tested under the European Standard BS EN 771-1 for resistance against frost attack or likelihood to effloresce (when soluble salts appear on the surface,” explains Mark Laksevics of York Handmade Brick, and this could adversely affect NHBC and house insurance.

“There have been reports of reclaimed bricks carrying dormant dry rot spores which become active when the brick is put to use.” There is also the matter of supply. Reclaimed bricks are often only available in limited numbers, unlike new bricks, and therefore making it difficult to find a match for any further extension work.

Cost

Good quality, machine-made, standard-size bricks: around £350 per 1,000 for good-quality, machine-made, standard-size bricks.

Handmade and reclaimed bricks: around the £700–£800/1,000 mark.
“Prices go up for specialised 2” (50mm) handmades — around 90p per brick for purpose made and well over £1 per brick for reclaims, as sourcing these can be difficult,” advises Mark Laksevics.

Brick Tinting

Brick tinting is a useful way of matching new bricks to old, blending in a bad extension or to make new brick repairs less noticeable. Brick tinting does not mean that the bricks are painted. It is a process that uses a chemical and oxide solution, using various colour dyes that have been chosen for the individual situation.

The solution changes the original colour of the brick rather than just coating it, which means that the brick will weather naturally and that the new colour cannot fade. Some companies, such as Extension Match, offer a lifetime guarantee on the service.

Matching Mortar

If you have spent the time and extra effort getting an exact match for your bricks, do not go and ruin it all with the wrong mortar. It is amazing how wrong new and different mortars can look sitting next to old mortar.

If the existing mortar is crumbling or in need of replacement, then you will in some ways find yourself in an easier position as the whole thing can be repointed using the new mortar. If, on the other hand, the mortar in the existing part of the building is sound, it can seem a bit of a waste of time to take it all out and repoint just for the sake of matching the new.

Some mortar specialists will match your original if you send them a sample, whilst others can carry out a complete chemical testing process to find out exactly what the existing mortar is made up of to ensure an exact match — although this will cost you around £200.

If the original section of your home uses lime mortar, then you would be sensible to ensure the extension does too. If not, then ensure you look at plenty of samples of what your new mortar will look like once dry in order to get a good match. And, if you are still not happy once the work has been carried out, the same companies who offer brick tinting services often also offer mortar tinting.

Matching the Roof tiles

As with brick, replica rooftiles can also be made to order and reclaimed tiles are widely available, although some roofers refuse to lay them, claiming it’s a time consuming job where hairline cracks that were previously invisible can cause a lot of wastage and slipped tiles later down the line. You should also be aware that if you are planning on mixing new tiles with old or reclaimed tiles, their guarantee may be compromised. Remember, it is impossible to know how much life a reclaimed tile has.

It is possible to source tiles to match originals by looking for a manufacturer mark on the back of the tile — often giving the design and age of the tile, making it easier to find reclaimed tiles from a roofing or salvage merchant. Be aware though that while reclaimed tiles have a weathered appearance, they may still not exactly match your originals if they have been positioned at a different orientation and have more or less moss growth.

New tiles can be made to look old using stains and sprays, but it is important to remember they will naturally weather over time. Applying a coating of a nutrient such as skimmed milk or yogurt, liquid tomato fertiliser or liquid cow manure can also help speed up the growth of moss and lichen to help the new tiles blend in with the old. It is also worth noting that when it comes to rooftiles, a slight difference between the new and old is far less noticeable than with bricks as they are viewed from further away.

Matching Stone

Stone extensions can be even harder to match to the existing property than brick. Being a natural product, stone obviously has variations in colour and tone, and if the building was built some time ago it will be very hard to achieve the same texture and weathered effect as the original. Unlike bricks, stone cannot be ‘manufactured’ to match the original, but there are a few ways to find a similar look.

• Obviously using the same stone from the same quarry will be a good start, but even this does not guarantee a perfect match.
• Ask your supplier to build a small sample wall to check how it will sit against the original.
• You will also need to work with the stone mason to ensure the new surface texture of the stone will match — various techniques such as ‘chiselling’ and ‘axing’ all produce a different look.
• You need to ensure the size and course height matches too.
• Having the original stone cleaned back to its original colour will also help.

Finally, if you are still worried, it might be best to build something completely contrasting — stone buildings look great teamed with glass, render and timber cladding.

We pride ourself in the high quality of property renovation services we offer. If you are about to start a property renovation project, whether its an extension or basement conversion, make sure your architect is on point with regards to the type and depth of foundation needed. Starting a property renovation project is daunting to say the least. As a homeowner, the question of “where to start?” is often overwhelming.

The SDA Build London team takes care of it all, from start to finish so that you don’t have to worry about the technical and regulatory requirements. Please do not hesitate to give us a call or e-mail us if you want any advice at all.

For a complete property renovation project, we usually start with the foundations. Various factors need to be considered including current foundation depths, soil composition and drainage systems amongst others. It’s key to get the foundation right when you are undertaking an extensive property renovation project. A foundation will not get passed by building control who will deem it unsafe for habitation if the latest building control regulations and standards are not adhered to. Before commencing full-blown excavations, we recommend that your builder digs a small area to assess current foundation depths. It is advisable to call your building control surveyor at this stage, who will be able to advise you on the depth and type of foundation you will require for your project.

Sourced from the Homebuilding & Renovation website, we found a handy guide on getting your foundation going.

What is a Soil Survey and Do I Need One?

A soil survey or investigation can help determine the type of foundations needed. This involves holes being dug at various points on the site and extrapolating the findings in each hole to assume the subsoil conditions throughout the site.

Soil investigations can prove very useful but are not a prerequisite. Most sites start without a formal soil investigation, relying instead on either the knowledge of the designer, or the local expertise of the building inspector.

What Type of Foundations Do I Need?

Simple Foundations

The standard routine is to place as little solid concrete as possible into trenches (minimum of 250mm) and then to build up from this in blockwork until ground level, where the walls switch to brick or stone or whatever the chosen external cladding should be.

This is known as a strip foundation (see image 3 below). A widely used alternative is to fill the trenches with ready-mix concrete to just below ground level (trenchfill, image 2) which saves labour but adds to foundation costs. Just above ground level, the footings are topped with a damp-proof course and then the ground floor is fixed.

Engineered Foundations

If the ground is deemed to be difficult, there are a number of options — all of them considerably more expensive than straightforward foundations.

The simplest solution is just to dig the foundation trenches deeper and then fill with a much greater depth of concrete, sometimes fitting sheets of polystyrene beside the trenches to act as a slip membrane.

However, there comes a depth (around 2.5m deep) beyond which it becomes impractical and dangerous to work, and the amount of concrete needed to fill the space becomes prohibitively expensive.

If the site requires deep foundations in more than a couple of spots, then it is now usual to use a different approach, most often piling, occasionally using concrete rafts.

Piled Foundations

Some housebuilders now use piled foundations on every site because the costs are predictable. Piles are driven into the ground and then filled with concrete, and the whole foundation gets topped with a ground beam to build off.

Raft Foundations

As the name suggests, a concrete raft  is designed to ‘float’ on the ground beneath. The structure is made up of an extra-thick floor slab, strengthened by masses on steel reinforcing. Rafts have the advantage of providing the base of a ground floor solution, not just wall trenching, but they are reckoned to be rather more complex to construct.

How Much Will My Foundations Cost?

Try as you might, the foundations are the one part of a building project that you cannot fully plan out until you start on site. Ground conditions vary and often problems only make themselves known when you break ground.

Costs will also vary depending on the foundation type you choose, with strip foundations being the least expensive.

It is also worth ensuring that you have a contingency budget available at this stage to be able to react to any unforeseen issues that may occur when you break ground.

How Do I Prepare the Site for Foundations?

A datum level must be set up for the eventual oversite level so that all trenches can be dug to accommodate that. On sloping ground, or with a design that employs differing oversite levels, that may mean that you should be prepared for shuttering with suitable 50x100mm timber.

You will typically need:

• mesh reinforcement in the foundation concrete
• compressible material for lining the trenches
• a polythene slip membrane
• cut metal pins to use as markers ready on site
• several rakes and pairs of wellies (you’ll be surprised how many people turn up for work in trainers)
• to be aware of any lead-in times. If the engineers have designed a foundation that requires reinforcement cages, these may have to be manufactured off site
• to think ahead to getting the services into the house, so get some lengths of pipe or ducting to take through the concrete.

What Factors Can Affect Foundations?

Tree Roots

Where the foundations are affected by tree roots (or their previous removal), you may be required to employ a fairly deep trench filled with concrete but with a compressible material to one or both sides of the external trenches to counteract any heave or expansion in the ground.

Water Pipes

Water pipes must enter the building at a depth of at least 750mm but no more than 1.35m below ground. If that means that they pass through a concrete foundation then they must either be laid prior to pouring or, better still, a duct installed for them to be pushed through later.

Sewage Pipes

If sewage pipes leaving the building have to be deeper than the top of the foundation concrete then they should also be ducted; they cannot be trapped within the concrete and must be able to move freely.

Electricity and Gas

Electricity and gas don’t usually need to be ducted or installed at this point as they are normally surface mounted. Finally, the building and warranty inspectors will have to approve the excavated foundations prior to any concrete being poured.

The information above is technical in nature and usually it’s your architect, builder and building control surveyor who will manage these details. However, if it’s your home or a home that you are developing to sell, we believe it’s important for you to  have as much information as possible.

If you are thinking about a rebuild or a refurbishment of a property you own, why not get us around for a FREE, no obligation consultation. One of our experienced colleagues will visit your site, discuss your needs and give you our recommendations.