Laying paving stones and gravel

[kitjohnson]

It's been a year since my house in Bangkok was completed (so grateful for all the help on Thaivisa.com) and so far it's a great place to live. One issue we're facing is that when it rains, the water hits the earth about 90cm from the house, splashes up mud and spoils the nice white walls. We've been planning on a pathway around the house but now it's really time to get to it.

 

The kind of design we're looking for is attached as an image of the concept, and also a render from Sketchup. It's single pavers arranged with gaps, like stepping stones but more formal. Surrounding them will be either gravel or pebbles, depending on how much it all costs. Pebbles would be nice but probably quite expensive. The entire area is about 100 square meters.

 

My question is how to plan the 'foundation' for this. When you're making paving stones that but up next to each other, it's important to lay both gravel and then sand, so make sure it's really level. But since our pavers are spaced apart, it's not quite so important that it's exactly level.

 

What's important to us is:

 

• no weeds popping up
• good drainage
• pavers remaining fairly (but not precisely) level over the years
• as cheap as possible. Our budget is just about all used up.

 

So I'm unsure what material and how deep we should use for this foundation. That's the question.

 

More details:

 

• The total area (including pebbles and pavers) is 98 square meters.
• The area of pavers if we use 30cmx60cm each is 32 square meters.
• This leaves 66 square meters of pebbles.

 

I found some concrete pavers locally, 30cmx60cm, for 70 baht each, which will probably do the job.

 

Thank you!

[kitjohnson]

One other question, is that we have blue PVC water pipes running alongside the perimeter of the house, just resting on the ground. Is it okay to just put gravel/pebbles on top of this, or do we risk damaging them from foot traffic over the years? This photo shows an example, with a bonus yellow pipe containing electrical cables towards the rear fence (just in case one day we want to light up said fence).

 

[bankruatsteve]

Yah, those PVC will probably get damaged the way they are now.  Anything to cover will help.  I would go with concrete but gravel fill might be OK.

[eyecatcher]

I am going to suggest you lower your sights a bit and remind you that pavings, gravel, tarmac, concrete whatever is going to be a life of on going maintenance....

weeds; they are as voracious as termites and you cannot stop them.

 

Even if you construct a concrete sub path then pave and gravel on top as I did the weeds and seedlings start because the seeds are being carried in the wind.

Its hard to believe but somehow those spores find dust or just moisture from a previous rainfall to grow

A lot of people believe geotex or polythene membranes stop weeds, yes for a period it stops growth from underneath, but again rain and dust collects and perfect for new windborne spores.

 

You are correct with the path build up, the usual "inch and half down" crusher is the way to go but not always readily available. 100mm needed really and well compacted.

If you  have that there is no need for the sand bed if you are going to bed the paving stones on a stiff mortar. A sand bed is only lying smaller blocks loose and butted up. Sanding up between stepping stones as your picture only leads to it being washed out aswell as the adjacent paver.

 

With your water pipes, if they are likely to be deep enough when covered by your gravel ie more than 6 inch and seldom crossed by foot traffic then I wouldn't worry unduly.

However you see some pipes floating across across areas and prone to stepping on and breaking a joint. Use your best endeavours to protect it with  some bricks under, or even a bit of concrete or maybe a blue soil pipe ripped in half and bedded over the pipe and then lost in the gravel.

 

costs of materials obviously vary but I have recently paid 800bt/m3 for inch stone, not crusher which is much cheaper, and 600bt /m3 for sharp sand

 

[watcharacters]

 

 

Load up on Round Up.

[eyecatcher]

2 minutes ago, watcharacters said:

 

 

Load up on Round Up.

or alternatively if you are a tight bastard like me, go for the backache instead

[watcharacters]

2 minutes ago, eyecatcher said:

or alternatively if you are a tight bastard like me, go for the backache instead

The SUPER  Round Up I've used in the past will probable be a partial cause of my death.

 

I can't remember if it was $100. a gallon or a quart.   But it sure does work!

[kitjohnson]

16 hours ago, eyecatcher said:

I am going to suggest you lower your sights a bit and remind you that pavings, gravel, tarmac, concrete whatever is going to be a life of on going maintenance....

weeds; they are as voracious as termites and you cannot stop them.

Fair enough: weeding will be needed, or a weedkiller!

 

16 hours ago, eyecatcher said:

You are correct with the path build up, the usual "inch and half down" crusher is the way to go but not always readily available. 100mm needed really and well compacted.

 

Here's my interpretation and conclusion:

 

From what I've read, anything from one and a half inches up to six inches for the crushed stone is recommended, depending on the soil below. Our soil seems quite clay-like to me, but I'm no expert. I guess we'll go for not more than 4" (10mm), but possibly less.

 

For the depth of the actual gravel or pebbles (and I'm talking small round stones here, not crushed or mixed with stone dust), would that just be dictated by the depth of the paving slab? If so we're only looking at about one inch.

 

If you  have that there is no need for the sand bed if you are going to bed the paving stones on a stiff mortar.

 

I hadn't thought about laying the paving stones on a mortar bed. Is that just to keep them still? Could you lay mortar directly on top of the weed barrier?

 

Currently my biggest question is about drainage. We already have drainage issues as the land doesn't slope away from the house, so that needs to be fixed by landscaping. But I'm thinking that with the little diagram I posted above, that we're goin to be creating here a little pool of water right next to the house. All the rain from the roof will be falling onto it. There's no damp course on the house (the contractor hadn't even heard of one and we didn't get it researched in time before the walls went up) and so having a poorly-drained path would surely lead to rising damp. Does anyone have any smart ideas to tackle this? Or will the crushed stone drain well enough, provided the land and path are on a suitable slope away from the house?

 

16 hours ago, eyecatcher said:

However you see some pipes floating across across areas and prone to stepping on and breaking a joint. Use your best endeavours to protect it with  some bricks under, or even a bit of concrete or maybe a blue soil pipe ripped in half and bedded over the pipe and then lost in the gravel.

That makes a lot of sense.

 

I'm really grateful for all this seasoned advice.

[kannot]

16 hours ago, eyecatcher said:

I am going to suggest you lower your sights a bit and remind you that pavings, gravel, tarmac, concrete whatever is going to be a life of on going maintenance....

weeds; they are as voracious as termites and you cannot stop them.

 

Even if you construct a concrete sub path then pave and gravel on top as I did the weeds and seedlings start because the seeds are being carried in the wind.

Its hard to believe but somehow those spores find dust or just moisture from a previous rainfall to grow

A lot of people believe geotex or polythene membranes stop weeds, yes for a period it stops growth from underneath, but again rain and dust collects and perfect for new windborne spores.

 

You are correct with the path build up, the usual "inch and half down" crusher is the way to go but not always readily available. 100mm needed really and well compacted.

If you  have that there is no need for the sand bed if you are going to bed the paving stones on a stiff mortar. A sand bed is only lying smaller blocks loose and butted up. Sanding up between stepping stones as your picture only leads to it being washed out aswell as the adjacent paver.

 

With your water pipes, if they are likely to be deep enough when covered by your gravel ie more than 6 inch and seldom crossed by foot traffic then I wouldn't worry unduly.

However you see some pipes floating across across areas and prone to stepping on and breaking a joint. Use your best endeavours to protect it with  some bricks under, or even a bit of concrete or maybe a blue soil pipe ripped in half and bedded over the pipe and then lost in the gravel.

 

costs of materials obviously vary but I have recently paid 800bt/m3 for inch stone, not crusher which is much cheaper, and 600bt /m3 for sharp sand

 

ants  will  burrow  thru sand, dont bother with it, personally  id  concrete the whole area and lay thos e slabs into it as you go  and then  2  inch chippings around on top of the concrete when cured. As mentioned weed s will grow in the stone chippings albeit more  slowly and are easy to pull out

[kannot]

12 minutes ago, kitjohnson said:

Fair enough: weeding will be needed, or a weedkiller!

 

 

Here's my interpretation and conclusion:

 

From what I've read, anything from one and a half inches up to six inches for the crushed stone is recommended, depending on the soil below. Our soil seems quite clay-like to me, but I'm no expert. I guess we'll go for not more than 4" (10mm), but possibly less.

 

For the depth of the actual gravel or pebbles (and I'm talking small round stones here, not crushed or mixed with stone dust), would that just be dictated by the depth of the paving slab? If so we're only looking at about one inch.

 

 

I hadn't thought about laying the paving stones on a mortar bed. Is that just to keep them still? Could you lay mortar directly on top of the weed barrier?

 

Currently my biggest question is about drainage. We already have drainage issues as the land doesn't slope away from the house, so that needs to be fixed by landscaping. But I'm thinking that with the little diagram I posted above, that we're goin to be creating here a little pool of water right next to the house. All the rain from the roof will be falling onto it. There's no damp course on the house (the contractor hadn't even heard of one and we didn't get it researched in time before the walls went up) and so having a poorly-drained path would surely lead to rising damp. Does anyone have any smart ideas to tackle this? Or will the crushed stone drain well enough, provided the land and path are on a suitable slope away from the house?

 

That makes a lot of sense.

 

I'm really grateful for all this seasoned advice.

If  you want to do a damp course an easy way is to buy tubes of damp proof  cream, drill the walls  3/4  the way thru every 8  inches or so  apart  then  inject the cream  it may certainly  help, doubt the stuffs  available here but I could bring it  in my suitcase if I was going back to the Uk , its  only  the normal sized tubes ( like silicone tubes)

[cornishcarlos]

Have you not considered guttering, stop the problem before it hits the ground ?

[eyecatcher]

I had exactly the same problem with rain hitting my unprepared ground onto my new yellow painted boundary walls. the beauty of the stone, and I used the grey "hin" you buy bagged or in a cube drop which is for concrete mix is that the rain hits it and 75% of the splashes fire in the opposite direction or else fail to make the splash bounce unlike soil and clay.

 

one comment on your drawn detail, its almost perfect. The brick edging you propose needs better support. If you can leave yourself the option of providing a narrow hand mixed concrete footing. it only needs to be 200mm wide and 50mm deep for a brick and then with your mortar mix during the bricklaying, just batter up the back of the brick in a triangle.

this will give a strong edge support for your path. I suggest you make that the first step of the whole operation.

 

As suggested above, a concrete path first and then layi the pavers and gravel ontop is the best way to go. I t gives you a clean surface to work from, you alleviate the need for the ground membrane, it can be sloped to carry rainwater away from the house and it stops termites humping up their mud mounds. I know it costs a bit more and is more effort but on a stone bed it doesn't need to be thicker 60mm.

 

keep your pavings away from the house wall, in the uk its standard practice to use the gravel abutting the house walls for the reason I mentioned above...it will not splash, with pavings, soil, grass it will; and there are many topics on here about people worried why their paint  is flaking off the render at exactly that splash zone.

 

if you are a diy er its a great project to get on with, and doesn't need much skill and tools, spirit level and rubber mallet...just a bit of hard work and a beer to look forward to

[kitjohnson]

Thanks a lot, @eyecatcher

 

I was also thinking of using the stones/gravel (I get confused with the terms) that they use in concrete mix as the cheapest option, and not a bad one either. And having this abutting the house is also exactly what I had in mind.

 

I hadn't thought about the effect that the angles of this stone/gravel would have in absorbing/deflecting rain: all the better.

 

I had seen an article saying to lay the edging in mortar, but had until now ignored that. But I can see the sense of it now. Pretty much essential.

 

So last question: is laying the pavers in mortar also essential, even if we go with crushed stone as opposed to a concrete bed?

[eyecatcher]

Yes always use a few mortar dabs, just one under each corner and one central. It first of all enables you to level the pavers, and create a slight fall for example.

it also stops the paving sliding and holds together an area of sub base that rainfall may just start washing away.

You also have to appreciate that even if you have the most perfect powerfloated concrete surface, those pavers are very often twisted with an uneven bottom surface so they  will rock about otherwise.

[kitjohnson]

Does anyone know what the local way of tamping down crushed stone is? It's about 100 square meters, so quite a lot to do. In the videos I've seen online you can hire a machine that looks something like a lawnmower to do it, or use a flat square thing attached to the end of a pole and tamp it down manually.

[MikeN]

The best way is with a mechanical compactor (the lawn mower like machine), hand tamping is ok for small jobs but not 100 sq.m. Where you would hire one I do not know but I imagine there must be somewhere in Bangkok. Or if you have clear vehicle access do as a friend of mine did.....lay a thin layer, drive your car over it many times, lay another thin layer, repeat as necessary. Not really the recommended way but it worked.

A quick search gives me http://Www.rent.co.th for equipment hire (look under road construction) but no prices given.

[themerg]

You need a 2-6 inches of sand below the gravel and paving.

Clay puddles. Sand drains. That a lesson from choosing golf courses after a hard rain in the USA.

[eyecatcher]

2 hours ago, themerg said:

You need a 2-6 inches of sand below the gravel and paving.

Clay puddles. Sand drains. That a lesson from choosing golf courses after a hard rain in the USA.

sand may be the way to go on a golf course but not here.

remember gravel drains ten times quicker than sand and supports paving at the same time.

Sand washes away with the rain and cannot support paving unless completed edged in.

[heybuz]

On 7/16/2018 at 10:01 PM, bankruatsteve said:

Yah, those PVC will probably get damaged the way they are now.  Anything to cover will help.  I would go with concrete but gravel fill might be OK.

don't put concrete over the pipes, concrete expands with heat and i see the pipes have joins they will pull apart or rupture in concrete.

[Lacessit]

If you can't beat them, join them. I have a native variety of grass that never seems to grow vertically, only horizontally. Maybe I'll patent it one day.

[Lucky mike]

Boiling water great for weeds !