I am getting a patio - advice please.

[r04DiE]

Post is too vague?

Whats the reasoning for concrete base?
What type of new paving material? Slab, block paving or a new resin finish? Other.

And what sub base have you got, clay, peat, wet boggy, trees close by?

And by Big boys do you mean a national like Everest? Ect

Thanks! OK, The concrete base was suggested by the local big boys who are not as big as Everest but they have been around our way for about 25 or 30 years and everybody knows them. They are expensive.

Paving type will be slab, not sure what the sub base is as I haven't lived here long and not done much digging. I reckon it might be clay further down but that is only a guess - sorry. For the teeny bit of digging that I have done, it's nice earthy stuff, pretty dry and easy to dig. Trees are conifers, about 20 feet away, about 30 feet high.

Would the chemicals be frost protector ?

I couldn't tell you, I am afraid. My wife was the one that spoke to them and I am not sure she asked them many questions at all!

No need for a concrete base.

Hardcore whacked down with a compactor. Slabs or stone laid with a full mortar bed. ‘Spots’ are not good enough. Pointed up with a 6:1 Mix. Avoid jet washing. Encourage hours of relaxation time.

If your budget allows, some of the ethically approved sandstones are only a smidge more expensive than the preformed junk you can get.

Thanks, I think the wife is in charge of the slabs though and colour will be the major decider here (naturally). Thanks for your comments on the base and relaxation time - that is very important!

Check what will be done to provide a damp proof course under the. patio doors. I've just had to have rotten joists replaced due to a poorly placed skimpy dpc.

Nice, will do this. The patio doors are already in, we have these french door things at the back of the house and the patio will run past them. There is also the door from the utility room and the door from the boiler room.

Here's my advice:

Don't bother with a concrete base - use compacted type1 or type2 aggregate (used under roads) as as sub-base. About £50 a ton Hippo bag from B&Q.

Stones are laid onto mortar on the compacted aggregate. whacker plates can be hired from Speedy Hire. Warning - heavy & unwielding!!.

Ensure the patio has a very slight tilt away from your property which makes water drain away. My patio is about an inch lower at one end so rain drains into the lawn.

Be very careful about cleaning - acid based cleaners can cause reactions with iron in types of stone and ruin your patio. Karcher stone jet wash detergent is OK on my sandstone patio.

Seal the patio with a good stone sealant to guard against oil spills, water etc.

Enjoy.

Great, thank you. hopefully the bloke doing the job will bring a whacker - I will see.

[QUOTE 5534421, member: 9609"]do is a favour and find out why they are suggesting a concrete base - never heard of that for a patio

4 inches hardcore well compacted, then lay the slabs on inch and a half dry sand/cement (6:1) then point it up with 4:1 cement[/QUOTE]Brilliant, thanks.

So, just to keep you all up-to-date, the patio man has been booked, but I will be asking him about all these things before he starts. Thanks to everyone for the input, including those that I haven't quoted. You've all been very helpful!

 

[Levo-Lon]

If its slabs, a good type 1 mot or similar will be fine 100mm after compaction.
Slabs should be on either a wet mortar mix with a mortar joint if its a natural product, You can use a tub of jointing too but its expensive on a large area.

Or a good sand and cement screed for most concrete paving.
Jointing as above.

Hope you end up a happy customer.

 

[captain nemo1701]

Don’t put any slabs directly onto clay as in shrinks & swells. My old patio was like this as the previous owners took a short cut & did it themselves. Result – a patio as flat as the Alps. My new one is 4m x 4m and took two tons of aggregate. Use compacted aggregate, which doesn’t shrink or swell & is also free-draining. About £50/ton from B&Q etc.

I note that you say you have trees about 30ft high & 20ft away from your house?. I’m a geotechnical engineer and trees fall broadly into three categories, high, medium & low water demand. They have ‘zones of influence’ around them and may shrink the soils (Leylandii are the worst!)

Zone of tree influence:

High water demand = 1.25 x mature height

Moderate water demand = 1 x mature height

Low water demand = 0.5 x mature height

The distance which trees of different species can affect building foundations can be obtained from NHBC Standards Chapter 4.2 Building Near Trees 2003.

It may be prudent to identify the species & work out if they might influence your foundations. Get professional advice though as chopping them down may cause the opposite problem of soil heave (expansion on re-hydration).

 

[Drago]

Just make sure you're house is big enough to fit a piano.

 

[r04DiE]

OK, an update:

He talks really fast but this is what he said, more or less:

Base: he will use stone, about 10 tons of it, type 1 mot, mentioned something about type 1 sand and cement - the patio and side alley are about 70m2. He is going down about 4". Pointing will be done with 4:1 and he said something about flat pointing, whatever that is.

I am off work for the first two days that he will be here and I said I might muck in as I like to keep busy. He seemed okay with that and said that he has no problem with me watching what he does or getting involved. I take that as a good thing.

The damp course for the patio doors he says is not a problem as he will be going below the existing damp course. Not sure if that is okay?

We also have a garden path that he will be replacing, its crazy paved - he said he might use that as the base for the new path with sand and cement (if it is solid enough).

Thanks!

 

[r04DiE]

Don’t put any slabs directly onto clay as in shrinks & swells. My old patio was like this as the previous owners took a short cut & did it themselves. Result – a patio as flat as the Alps. My new one is 4m x 4m and took two tons of aggregate. Use compacted aggregate, which doesn’t shrink or swell & is also free-draining. About £50/ton from B&Q etc.

I note that you say you have trees about 30ft high & 20ft away from your house?. I’m a geotechnical engineer and trees fall broadly into three categories, high, medium & low water demand. They have ‘zones of influence’ around them and may shrink the soils (Leylandii are the worst!)

Zone of tree influence:

High water demand = 1.25 x mature height

Moderate water demand = 1 x mature height

Low water demand = 0.5 x mature height

The distance which trees of different species can affect building foundations can be obtained from NHBC Standards Chapter 4.2 Building Near Trees 2003.

It may be prudent to identify the species & work out if they might influence your foundations. Get professional advice though as chopping them down may cause the opposite problem of soil heave (expansion on re-hydration).

OK, thank you for this and I will look into it and maybe have a measure. The trees are conifers, that's all I know!

 

[r04DiE]

Just make sure you're house is big enough to fit a piano.

We already have a piano!

 

[Heltor Chasca]

^Fine about his comments on the damp course. You may proceed

 

[r04DiE]

^Fine about his comments on the damp course. You may proceed

Great, thank you, my man!

 

[Ming the Merciless]

The concrete base will be to ensure the bodies as above are not discovered.

 

[classic33]

The concrete base will be to ensure the bodies as above are not discovered.

Until the flesh has rotted away leaving a hole in the ground/concrete. Causing a collapse.

 

[Levo-Lon]

You perhaps miss heard him.
4"? 100mm total dig? So 50mm hardcore I'll guess a 32mm slab and 25mm+ sharp sand and cement screed?
Or sand and cement mortar? Which would be a building sand cement mix.

Not really ok imho
If its a 100mm hardcore then the bed and paving, you would need a 150mm dig.

If he's going to use about 10 ton, id think its ok as that would be about right at 80-100mm base.

Damp course for patio doors.
Usually 150 mm below dpc then a step at the door. This can change a little depending on where patio finishes, ie 150mm of gravel at the walls ect but 100mm below minimum.
Acco drains can help but water needs to flow away wherever possible. Which you know already going by your post.

 

[r04DiE]

You perhaps miss heard him.
4"? 100mm total dig? So 50mm hardcore I'll guess a 32mm slab and 25mm+ sharp sand and cement screed?
Or sand and cement mortar? Which would be a building sand cement mix.

Not really imho
If its a 100mm hardcore then the bed and paving, you would need a 150mm dig

I will ask him!

 

[Levo-Lon]

I will ask him!

Ok, i was still adding but im sure you read it.

Just a quick tip for easy digging guide.
A course of brick and the joint is about 75mm so 2 course is 150mm
When dug out and ready for stone you would expect to see 3.5- 4 courses below the black dpc line.
Services may be exposed shallow pipe ect but that will all be covered again when complete.

Have fun digging..

 

[r04DiE]

OK, thanks @meta lon! My mate came round today and he reckons the patio should end up about 2 courses below the dpc so that agrees with what you are saying. He has a bit more experience in building projects than I do. I will clear the depth with the bloke when he gets round.

Thanks!