DIY porcelain patio

Once the extension was done, the outside of the house was a complete mess. Stepping out of our new bi-fold doors into a sea of mud wasn’t ideal, especially with Basil coming in and out all day. So after fitting the kitchen, the next job on the list was the patio.

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Why porcelain tiles?

There are a few options when it comes to patios and we spent a long while considering each. We ended up opting for porcelain because they’re man-made and so come in a massive range of colours and styles. They’re also easier to maintain than natural stone options as they’re non-porous. They won’t go all green and grim-looking like other options and they wipe clean just like indoor tiles. The last thing we prefer about them is that they’re quite contemporary-looking without being too modern.

The obvious negative is that they cost more than natural stone alternatives. Having said that, we paid £28 a square metre which isn’t crazily expensive, and our patio is only 19sq metres (6.3×3). Check out Prices Paving if you’re after some sensibly priced patio tiles/stones.

Sub-base

First up, everyone’s favourite job: digging.

I planned for the patio to meet the house at about 18cm below the damp proof course (2 blue bricks down on our house) and to fall 1cm every 60cm away from the house to encourage water off the patio. I used wooden stakes to mark the finished height of the patio and dug down to around 16cm. This allowed for 10cm of sub-base, a minimum of 4cm mortar and the 2cm thick porcelain tiles.

To build a 1 in 60 fall into the peg height, I spaced the pegs by just under 1.8 metres and used my 1.8 metre spirit level with a 3cm chunk of wood sat on top of the peg furthest from the house. That way, when the 180cm spirit level showed as level with a 3cm spacer at the lower end, I knew the lower peg was 1 in 60 fall from the higher peg (180/3 = 60).

Using a mattock is a massive time saver when digging by hand. Soon enough, the area was dug out to depth, allowing an extra 15cm or so around the sides.

The best sub-base to use for a patio is MOT type 1 which you can get in 850kg bulk bags for around £40 each. There are loads of calculators online to help work out how much you need. If you need around 7 or 8 bags plus, it’s probably worth buying a loose load rather than bagged which works out much cheaper.

I wheelbarrowed the sub-base onto a permeable membrane which stops the sub-base mixing with the earth.

After spreading about 5cm of sub-base, I gave it a good old whacker with a hired compactor plate. This was fun. Pretty sure I went overboard with the whacking.

I repeated this, regularly checking the gap from the top of the pegs to the sub-base. When this got to 6-7cm (4-5cm mortar + 2cm tiles), it was ready.

With all the whackering done, I cut off the top of the pegs and got ready to lay the patio.

Tile cutting

I wanted to keep things as simple as possible but there was a little cutting to do around drains. I also cut a couple of tiles in half so that the tiles could be laid in a brick pattern. 

A lot of stuff online says that you need fancy gear to cut porcelain tiles because they’re incredibly hard so cutting blades get red hot. After a loads of research, I came across this diamond blade for a 4.5 inch angle grinder that’s specially designed for cutting outdoor porcelain tiles. It worked a treat.

Laying the patio

With the tiles cut, the time came to actually lay the things. There are a few different jobs that you ideally need to be cracking on with at the same time so this is definitely a 2 man job. I tried a day on this by myself and got hardly anything done plus knackered my back as the 90x60cm tiles are heavy and awkward.

First things first, get the cement mixer going. You could mix by hand in a wheelbarrow, but this is a pretty bleak job if you’ve got a decent-sized patio. We bought this one but you can hire them pretty cheap. I used a mix of 1 part cement to 4 parts sharp sand, keeping it quite dry. In hindsight, I should have made the mixture a little more wet as it’d have been more workable and easier to tap the tiles down to their final level.

Before plonking the tiles down, there’s a crucial extra step that needs to be taken for porcelain tiles. Because they’re non-porous, they won’t properly adhere to a normal mortar mix so you need to apply a generous amount of slurry primer to the back of each tile before laying. You can buy the primer ready-made but it’s cheaper to make your own which is just SBR bond mixed with cement to a thick consistency.

I then slapped it on the tiles with a wallpaper paste brush. I say slapped, this stuff is seriously messy so needs to be handled carefully. If you get it on the top face of the tile it needs to be wiped off straight away with a damp sponge or it can permanently mark. It’s worth doing this job a fair distance away from the other tiles to reduce to chance of them getting splashed.

The first tile you lay is the most important as it sets the direction and level of every other tile. Needless to say, it’s worth spending time on it.

Once I’d mixed roughly enough mortar, I laid a tile on top and checked the levels were about right. You’re best off testing the levels with an un-primed tile because if you use a primed one to check the levels and have to add/remove mortar, the mortar will stick to the underside of the tile and reduce the primer’s effectiveness.

I was aiming to have them being perfectly level from left to right, and at a 1 in 60 fall away from the house using a 60cm level and 1cm spacer to get this right.

It may take a couple of goes to readjust the mortar bed with a trowel until the tile sits at the right levels, tapping the tile down into the bed with a rubber mallet. As well as getting the levels spot on, it’s really important that the tile makes good contact with the bed. I’ve read that it needs to be 70% as a minimum, but the safe bet is to aim for 100%.

Once the first tile is down you get into a bit of a flow. The previous tiles dictate the positioning and levels of subsequent tiles which is a big help. A top tip for helping work out what level to lay the bed to is to spread a long spirit level between two tiles you’ve already laid. You want around 15mm to be showing under the spirit level as this will compress slightly when you tap down the 20mm tile. I read about this tip on this blog post which was massively helpful.

One you’ve got a roughly 15mm gap between the spirit level and mortar bed, place an un-primed tile down to see how proud it sits of tiles around it. The more tiles you lay, the better you get at gauging how much the tile will drop down once tapped down with a rubber mallet. As ever, make sure you’re checking the levels as you go.

We went for 5mm spacers between our tiles. Making sure the spacers fit snugly into the gaps is really important as any error here would affect subsequent tiles. If you find the gap opens up while tapping to tile down, you can tap the tiles from the side to shift them back into position.

As great as porcelain tiles look, they are really unforgiving if you don’t take the time to get the levels consistent. They’re very flat and are spaced so close that any deviation from one tile to the next is very obvious.

If, like me, you’re laying porcelain tiles for the first time, I’d really strongly recommend not rushing things. Even with two us on this job, we were laying around 2 tiles an hour which sounds horrendously slow but if we’d gone any quicker we’d have had to compromise the accuracy. Not only would any errors look rubbish, they could also lead to water pooling on the patio which with impermeable porcelain tiles would be a big problem.

After many hours, the first 2/3 of the patio was laid. I actually left the the last 1/3 until a few months later as there used to be a pond there which I wanted to allow to settle over winter before laying the patio over it.

Grouting

After a couple of days, the mortar had cured and the patio was ready to be grouted. There’s a baffling number of options to grout patios but we decided to use Marshalls exterior jointing grout because of how quick the process is. The product comes in a powder form so you mix it in a bucket as per the instructions. But before doing this, there are couple of things you need to do first.

The mix is surprisingly wet and thin, and so it’ll seep out of any gaps around the outside of the patio if you don’t plug them. I pushed some damp sand up against the gaps which did the trick.

The other job pre-grout mixing is to lightly spray the tiles with water. This is a really important step as the grout can stain if it’s left to dry on the tiles. By moistening the surface, the grout is less likely to adhere to the face of the tiles.

Next it’s time to mix. I used around 20kg (it comes in 25kg buckets) of the powder for our 19sq metre patio (90x60cm tiles, 5mm gaps) and used a paddle on my combi drill to mix it up. The mix seems very wet at this point but that’s how it should be. If you decide to use the same product, here’s a really helpful video.

After mixing thoroughly, the countdown is on as you only get 20 or so minutes until the grout stops being workable. Roughly dribbling it out onto the gaps saves some time.

The best thing to spread the mixture around is a long squeegee, working the grout over the cracks from multiple directions to make sure the product finds its way into the gaps and fills them up. I only had a tiny shower squeegee and was too tight to buy a long one just for this job but it did the trick. If I had 15sq metres+ to grout in one go I’d either have used a long squeegee or got help from someone else with another miniature squeegee.

After filling the gaps and looking over them again to check they were full, the patio looked like this.

At this point, I found that giving the area a very light spray with the pressure washer was a good idea as it reduced the chance of the grout curing on the tile face. I then whapped out my hilariously small squeegee again to scrape most of the excess off. There’s a slight texture to our tiles and so there was a thin film of grout sat on top after squeegeeing.

Then, I waited… As per the instructions, you’re supposed to wait a minimum of 30mins before spraying away the excess. It was a fairly cold day so after around 40 mins, I fired up the pressure washer. This step is really satisfying as it’s the first time you see how the grouted tiles look.

I was very careful not to directly spray the grout to avoid it being pushed up and out of the gaps. Soon enough, all the excess was washed away and that was that.

Patio steps

As the patio sits almost 20cm below the top of the bi-fold threshold, we decided to add a step. Luckily for us, the place we bought our tiles from supplied treads and risers as well as the standard tiles.

There’s a 13cm gap between the bottom of the bi-fold lip and the patio, so I was aiming for a roughly 12cm high step. This would be made up of 15-20mm mortar, 65mm brick, 15-20mm mortar and finally the 20mm thick tile tread.

I started with a dry lay so that I could mark the position of the bricks on the walls and tiles. This also helped me work that there would be no need for any bricks to be cut. I used a speed square to make sure that the tiles would be positioned square to the house.

From then on, the process was very similar to laying the tiles. I slapped down some primer and then trowelled on some mortar before laying the bricks and tapping them down with a rubber mallet.

I wasn’t overly precious about the levels of the bricks as slight adjustments could be made when laying the mortar bed that would sit below the tiles.

When it came to laying the second row, I used a combination square to make sure they were consistently 27cm from the house. As the treads are 33cm deep, this would allow for 2cm mortar, 2cm riser and then a 2cm overhang.

I was very careful to remove any mortar & primer that spilled out with a wet sponge to avoid any staining. You can see on the below photo what the primer looks like if you accidentally splash it on the tiles. It sets ridiculously quickly and is almost impossible to remove so have that sponge at the ready.

That was the first stage complete, so I left the mortar to cure until the next day.

I started by laying the treads on top of the bricks. After spreading mortar, I primed the back of the tile and plopped it on top and used spirit levels to check it was level from left to right, and allowed a 1 in 60 drop from back to front.

I’d laid the mortar bed below the bricks too thin which meant having to make up the height with a fairly whopping layer on top of the bricks.

Because of the small gap between the two rows, every 30cm or so I added a small pile of mortar to reduce the area of the tile that would be unsupported.

Onto the risers. I had to cut these so I measured the gap from the patio to the underside of the step and whapped out the angle grinder.

I transferred the measurements onto the riser, removing 5mm to allow a gap the same size of the spacers, and very carefully followed the line.

I should warn you that cutting porcelain tiles creates a humongous amount of fine dust so PPE is really important. Regardless, it’ll still add about 20 years.

I squashed some mortar up against the front brick, primed the riser and tapped it into position. I kept the mortar really dry to help keep it in place.

And then, finally, just the side of the steps were left to do. Fortunately, I had a spare tile that I used to cut these out of.

After fixing the sides in place, the step was left to cure before grouting.

Grouting the step

The only difference between grouting the tiles and the step was that the grout needed to be mixed a lot thicker for the step. This is because gravity would have dragged a wet grout mix out of the vertical gaps so I kept it pretty dry and pushed it into the gaps by hand. I then sponged away the excess and used a finger to shape the grout, just as you would with sealant or caulk. Once partially cured, I pressure washed the excess away and finally, the patio was complete.

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I’d probably say that this project was one of the trickier ones that we’ve done. As I mentioned before, these tiles are incredibly unforgiving because of how closely they’re positioned and the fact that any dodgy levels can lead to water pooling. Certainly not a job that can be rushed, but we’re really happy with how they look and glad we went for porcelain as they’re so easy to clean.

I still need add a gravel channel at the front of the patio which will separate the lawn from the tiles.

Cost-wise, the whole thing came to just short of £1K, with the tiles accounting for around half of that. I’m not sure how much it’d cost to get a professional in to do this job, but I’d guess it’d be over £2K.

Materials

• Permeable membrane
• MOT type 1 (sub-base)
• Sharp sand
• Cement
• SBR bond primer
• Outdoor porcelain tiles
• Exterior jointing compound (grout)

Equipment

• Mattock
• Shovel
• Wheelbarrow
• Wooden pegs
• Hammer
• String line
• 180cm spirit level
• 60cm spirit level
• Whacker plate
• Angle grinder with diamond blade
• Cement mixer
• Mixing bucket
• Combi drill with mixing paddle
• Wallpaper brush
• Trowel
• 1cm spacer
• Rubber mallet
• 5mm tile spacers
• Pressure washer
• Squeegee