Thursday, August 20, 2009

Laying patio slabs, DIY style

We've been engaged in a new project, this time to turn the garden into the little oasis of peace and calm you see in the picture.

The original garden was typical Irish suburban, much like the builders left it 30-odd years ago. A grass lawn, some overgrowth of shrubs (and briars), and a tumbledown shed.

At first the plan was to remove the old shed, perhaps simply pave the area as a barrier against the re-emergence of briars, then replace the structure with another shed. But once we'd taken out the rotten timber, shrubs and weeds, the area was such a natural sun trap that it seemed a pity to give it over to another hostel for unwanted junk. So the idea of a patio was born.

A growth of ivy was taken off the boundary wall and the ground thoroughly dug to eliminate any root systems of this or the troublesome briars. The ground was then roughly levelled to give a firm footing for the structure that would eventually go on top. As the site sloped towards the house, any digging at this end would mean that there would be less as one worked out of the corner (provided, of course, the ground remained firm underfoot, which it did in this case).

Despite the precaution of digging up roots and weeds, these can grow back over time, so to inhibit these a membrane is laid, leaving enough overlap all around. Membranes can be bought by the roll in most DIY or Garden centres and they are pinned to the soil to stop slippage using plastic pegs that can be bought seperately. The membrane is water permeable, so the underlying ground won't dry out, useful if you plan on having plants coming up through it, for example. The roll is about four to five feet in width, so it's necessary to overlap sections and (as in this image) seal the overlaps with gaffer tape.

I proposed enclosing the supporting sand base to the slabs in a ring of concrete blocks. The blocks were laid on a bed of mortar made from sand and cement laid directly onto the membrane. There is no additional digging as I'm relying on the ring of blocks not to move on the already dug and stable ground. I suppose time will test that theory. The membrane is then covered in medium washed sand obtained from a builders' providers.

To fill the first "cell" took about two tonnes of sand. The sand is then screeded with a straight timber so that it can be levelled off. Once any imperfections have been filled or planed with the shovel as necessary, the surface is ready for the slabs to be laid out.

Naturally the cats had to try walking on the surface first to see if it was up to standard.

We bought Indian Quartz slabs from Roadstone and as they came in three different sizes, they were first laid out to test the pattern. The desired effect was a rough surface, and these slabs come with a naturally uneven one. The slabs would ultimately be mortared securely into place, but for now the laying out was simply done dry.

A little water, however, shows you the true colour of the slab.

The slabs were laid with about a two-inch gap between the outer edge and the boundary walls. This eliminated cutting and was the best solution in that the back wall and side walls were not at 90 degrees to one another, so keeping back a bit was best. The gap was filled later using some sand and a topping of beach cobbles for a decorative and pleasing effect. The slabs were also laid with about an inch and a half overhang over the concrete blocks. This produces an image of the patio "hanging" in mid air.

The first cell having been laid out, I decided to press on and add the next piece, which was to make the patio a kind of inverted "L" shape. Again, the soil was dug back to a reasonable level, and blocks laid on membrane to form edges for the cell. This took nearly three tonnes of sand to fill up, being a larger area.

Finally, the slabs were laid in their final positions -- checked by use of a line and, of course, a spirit level -- with a good bed of mortar underneath. There are few shortcuts here: each slab has to be bedded thoroughly, no "five blobs" work will do!

The slabs in the first cell were grouted using a barely-moist mix of sand and cement. I wasn't pleased with the outcome, but felt better when the grout lines were emphasised by dragging a pointed stone along them while still not quite gone off. This caused a more pleasing profile (you'll see a "Before" and "After" photo from the other section later).

With the first cell all but completed, we hung some sheets of water reed on the back wall and along the side. This was attached to the wall on wires strung between eye bolts fixed to the wall with rawlplugs. It hovers about an inch above ground level so that water can run off it.

Patio containers were starting to make their appearance at this stage, as the garden centres were being browsed for bargains... In the foreground are some lavendar plants which had been planted into the soil before we thought of doing the patio. Not wishing to disturb these, I resolved to build around them.

With the slabs laid and the grouting just about finished in the second cell, the grout lines were tidied up by scraping with my trusty pointed stone. The waste was brushed off lightly with a broom to give a satisfactory finish...

The next stage of the job involved tackling the area off the patio. I envisaged this area being gravelled, so we chose some pebble which would complement the colour of the patio.

The first job was the removal of the sod from the area to be gravelled, or pebbled, if you prefer. This took place over the course of a week when it never stopped raining and I didn't expect any work to get done. There was quite a bit of slipping and sliding involved, but it was otherwise straightforward. An old kerbing put in around the lavendar was taken out.

The pebbles arrived when it was raining, but I persevered, quite late in the day, quickly laid out some membrane (cutting slits in it for the existing lavendar plants) and threw down some barrows of stones "just to see"...

This high pink colour of the pebbles was caused by pink sand stuck to it which washed off nicely over the coming days. The pebble is a lighter pink, with some occasional white and black stones.

Looking back towards the house, you can see where I corralled the pebbles in another line of concrete blocks, this time set on edge and in a shallow foundation of sand and cement. Some of the smaller flags made stepping stones through the pebble, and a fountain (the electric pump's cable fed through a conduit under the pebble to prevent wear as the stones move underfoot) added a nice feature whose trickling water adds a restful atmosphere when one is sitting out.

That concludes the work two-thirds of the width of the garden. The other side having a dilapidated wooden fence and hedge it was necessary to have these pulled out and a new garden wall constructed before continuing with the rest of the paving work. I'll post more information on that later project when I can.


Jo said...

That looks lovely Willie. joan

Jo said...

Testin my name here..bear with me.

Jo said...

Ah ha, did you fix that Willie ? XX

iMADEtheBBC said...

superb ! that really is superb.

I'm getting ideas about replacing the little bit of grass in our back garden.

Willie_W said...

Thanks Joan and Peter.

Joan>> Simply log in before posting, it then uses your log-in name.

Peter>> It's heavy work, but satisfying. Although the paved area no longer has weeds, there are new matters to look at, like wind-blown weed seeds trying to grow in the grout lines, or moss starting up in any area where water might lodge.

The pebbled area also isn't immune from weeds, this time growing *down* rather than up.

On the plus side, one can always remove the containerised plants and pick out anything that shouldn't be there. But, as you can imagine, there is no more grass cutting, which is great.

We've spent more time in the garden this year simply because we have somewhere to sit out now. And the next patio is planned as about a yard wider to accomodate a dining table and enough room to fit people around it. There were some delays in getting the wall built and the patio itself has just been started. Hopefully, when my health gets back to normal, I can press on with that part of the project.

Tea and Margaritas in My Garden said...

That is lovely!
Looks like you`ve been very idle as well :)


Willie_W said...

Yes, Tea. We're a right pair, aren't we? :-)

Brad the Builder said...

Excellent! Great article!

Willie_W said...

Thank you, Brad.