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Order by phone 01285 656738 or Contact Us Online

How To Install Flagstone Flooring

Not Sure how To Lay Your New Tiles? Take a Look at Our FAQS

Browse the menu options for more information and advice.

What size of notched trowel should I use?

When laying larger natural stone flagstones, you should use 10mm or greater. Many people opt for 20mm – it provides a deeper bed, which is more forgiving.

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How Do I Prepare My Floor for Flagstone Installation?

Choosing to use Flagstone tiles leaves you with a selection of design options, and one important consideration is the laying pattern. Do a dry run with your tiles to check you are happy with the layout. It’s much easier to change the design before the mortar has been applied. Try a variety of different patterns before deciding on your final look. And make sure the floor is level.

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Should I Seal the Flagstones Before Laying Them?

No – you should seal them after they’ve been laid and grouted. It’s wise to seal them again, once you’ve finished grouting. Do make sure your tiles are clean first though – you’ll find lots of specialist stone cleaners on offer.

All the stone shown on our website is fully sealed, so you know what to expect from the end product. We do recommend visiting the showroom though – it’ll help you to fully appreciate how the stone looks in real life.

We stock two brands of sealant – and all our displays are sealed with one of these. One brand is a standard solvent-based impregnator sealant; this darkens the stone by a few shades. It also highlights the inherent characteristics of the stone, including veining and fossil content.

The second brand is known as a clear seal – it’s rapid drying and has a minimal effect on colour.

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What colour grout should I use?

Choose a darker colour in areas that attract more dirt, such as kitchens and utility rooms.

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Can I Lay Stone Tiles on My Timber Floor?

Yes. It’s wise to strengthen the floor with plywood first though. You should also use a flexible floor tile adhesive and grout – this discourages tile cracking.

Ensure the floor does not flex under the weight of the tiles. It’s best to calculate the weight of heavier tiles, including travertine, marble and limestone.

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I Removed My Old Parquet Floor, Which Was Covered with Bitumen. Can I Tile Straight on Top of It?

No – it’s best to remove as much of the bitumen as possible. Afterwards, you can prime the floor with a latex smoothing compound.

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How do I firm up my timber floor?

Decide whether you need to completely replace your timber floor before laying natural stone – this could be the most sensible option. Other less drastic measures include replacing a few floorboards and screwing others down.

You could simply cover the floor with 12.5mm or 17.5mm plywood or blockboard.

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Is there a special adhesive to use on timber?

Yes – you’ll need a flexible adhesive, designed for use with timber.

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Does a Floor Have to Be Level Before You Can Affix Stone Tiles?

Yes, although minor bumps and hollows can be leveled by applying more or less floor tile adhesive.

A dry level screed is the ideal surface for laying stone flooring. It must be clean, dry and grease free.

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How flat does my substrate need to be?

The flatter the better – you certainly don’t want any high points. You can overcome any dips with the aid of a levelling compound – or by building the area up with extra adhesive.

Which Levelling compound should I use?

It’s best to use a latex-based leveling compound in the following areas:

• Outdoors
• Places that may get wet
• Floors with no damp proof membrane
• Instances where your levelling compound will be below the damp proof membrane

If you need to build up certain areas, you can use water-based levelling compounds and aggregates. They’re great for dips of between 1.5mm and 40mm.

Before applying levelling compound to a concrete floor, you should use an acrylic primer to prevent bubbles forming in the compound.

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Can I Have Underfloor Heating with Stone Tiles?

Yes – stone conducts heat, so it’s the ideal surface. This will allow the heat to rise naturally.

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I Have a Wet Underfloor Heating System. Does This Require Any Special Treatment?

Yes – you’ll need to take a few extra steps. Newly laid screed needs time to dry – this prevents any moisture being absorbed into the stone, hence reducing the likelihood of discolouration. A millimetre of screed takes one day to dry, whereas one inch takes a week – it’ll take an extra week per inch, so can easily add up to 3-4 weeks.

Once dry, you’ll need to gradually heat your floor to full running temperature over the period of a week. You should then run it at full temperature for a week, before turning it off and allowing it to cool across a week.

This allows the concrete slab to develop hairline cracks, which allow for expansion when your underfloor heating is working. You must also use a flexible adhesive and grout.

If you don’t have the time for this, you can use a decoupling mat. This means you can lay the stone one week after laying the concrete.

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I Will Be Fitting Electric Underfloor Heating; Does This Require Any Special Treatment?

Yes – you should use a thermally insulating backer board under your cables. This stops you losing heat. As a bonus, the board is waterproof – making it especially useful in the bathroom.

Cover the tiles with flexible tile adhesive or a latex levelling compound. This reduces the likelihood of damage during tiling.

Finally, you must ensure there are no air pockets around your cables – as this will cause hot spots and eventually a fault with the cable.

You should use flexible tile adhesive and grout.

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