Firstly congratulations on a great site. I'm renovating my house and a drive is on the cards so i'll be in here for hours and reckon that book can be added to my library.
On to the subject at hand.
I live on a hill and if i walk round the back of the house i go down about 3ft terrace drop to a conrete slab type patio before walking up steps into the kitchen. Essentially i was going to deck on top of the concrete and flatten things out. Then i got thinking - i've a load of paving blocks about inch and a half deep and 6"x6" that are just sat doing nothing, what about laying these on a timber structure and having a nice raised patio which won't get slippy and ladies in heels can walk on.
I've searched and to date haven't been able to find anything advising how i would go about this - ie if i use the deck methodology for the frame do i use ply on top of this with a membrane to support the block (and risk it rotting) or is there a better more professional way / product designed to be used instead.
Spoken to decking suppliers and builders merchants and they've never heard of anyone doing this (well in the Belfast area at least).
I don't want to build a retaining wall and infill as it's a lot of area to fill..... I may be talking poop and have just opened myself to ridicule but it seems like a doable idea. All help greatly appreciated.
Cheers
Ed ???
Paving a deck?! - Lost and need advice
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Ted
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Someone asked me to lay a patio on a flat roof above their kitchen once. I refused and told him to go and seek out a structural engineer.
Your situation is not so serious; ie, the patio isn't going to fall into a room of your house. But how high are you wanting to set this patio off the ground? 3' high?
My instincts tell me that I would be more inclined to make a solid base.
You don't want your suspended patio to collapse, particularly if your pet dog has managed to climb underneath it at the time. A patio weighs a lot; you will need bloody strong timbers to support it, you, your guests, bbq etc. But 3' is a hell of a gap to fill...
LLL will be along with an answer no doubt.
Could he bulk up a base with polystyrene and pour a (reinforced?) slab on that to lay slabs on top of?
Your situation is not so serious; ie, the patio isn't going to fall into a room of your house. But how high are you wanting to set this patio off the ground? 3' high?
My instincts tell me that I would be more inclined to make a solid base.
You don't want your suspended patio to collapse, particularly if your pet dog has managed to climb underneath it at the time. A patio weighs a lot; you will need bloody strong timbers to support it, you, your guests, bbq etc. But 3' is a hell of a gap to fill...
LLL will be along with an answer no doubt.
Could he bulk up a base with polystyrene and pour a (reinforced?) slab on that to lay slabs on top of?
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doake
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Thanks Ted, it'll be about 3' high, enclosed round the sides and about 12'x12' square with steps down to the lower garden. The house is T shaped with the kitchen sticking out the back, thing is that the garden is level up to the wall where the kitchen door is which is at the side then the garden drops, on top of that i converted a window into a patio door which would walk out onto this raised patio
All that you mention has ran through my mind, will it rot, will it take the weight of the blockwork and people etc. The handy thing is that the existing base was poured about 1954 and is a good foot thick of concrete with little settlement movement in that time so i can whack as many posts in as needed.
I've even thought of a steel structure, but then i remind myself that i'm only considering using the blocks as i have them piled up from years ago and i thought it'd be much nicer if i can use them than plain decking timber.
I've even considered using 3'x2' paving slabs on top of the timber or steel as a base to put the block on, but that probably more than doubles the weight.
All that you mention has ran through my mind, will it rot, will it take the weight of the blockwork and people etc. The handy thing is that the existing base was poured about 1954 and is a good foot thick of concrete with little settlement movement in that time so i can whack as many posts in as needed.
I've even thought of a steel structure, but then i remind myself that i'm only considering using the blocks as i have them piled up from years ago and i thought it'd be much nicer if i can use them than plain decking timber.
I've even considered using 3'x2' paving slabs on top of the timber or steel as a base to put the block on, but that probably more than doubles the weight.
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Stuarty
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Id agree with Ted, id build it on a solid base. Id block the outer edge and fill the gap with type 1 or even infill. Even a concrete slab would do, just depends how much you wish to spend. You must remeber when you are building a frame and setting a slab ontop of it that only the edges of the slabs are really supported leaving a hollow under the bulk of the slab, basically, the slabs will be very weak.
Timber also flexes when weight is put upon it too, and it can warp over time, so your nice level patio could end up being up and down in a few years time
Timber also flexes when weight is put upon it too, and it can warp over time, so your nice level patio could end up being up and down in a few years time
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lutonlagerlout
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doake
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Points mentioned are exactly why i asked. What will retain the block? Imagined they would effectively be contained in an outer frame. Noise? Good point was hoping someone would have had the answer 
This is the thing, no-one's seen something similar (yet) but i might just give it a go - if i do i'll record it and send it in. What it looks like all depends on the effort put in.
Haven't given up hope that someone may have a pointer or two. Infact that's they key - you've got the experience of the pitfalls that may happen - how would you overcome them? So if i made a base on pillars using 4x4 posts say at 400 centres or 300 and topped that with 2 layers of ply say inch thick making a 2" bed. Then maybe either bitumen on that or a 1200 dpm. what next? Any ideas feel free.
1200 dpm might get holed so maybe not the answer unless it has a cushion on top of it (similar to those used in ponds)- again i may be wrong but as you guys have years of experience please make a suggestion (don't bother isn't a valid suggestion )
If it works great - if it doesn't then it's something learned
This is the thing, no-one's seen something similar (yet) but i might just give it a go - if i do i'll record it and send it in. What it looks like all depends on the effort put in.
Haven't given up hope that someone may have a pointer or two. Infact that's they key - you've got the experience of the pitfalls that may happen - how would you overcome them? So if i made a base on pillars using 4x4 posts say at 400 centres or 300 and topped that with 2 layers of ply say inch thick making a 2" bed. Then maybe either bitumen on that or a 1200 dpm. what next? Any ideas feel free.
1200 dpm might get holed so maybe not the answer unless it has a cushion on top of it (similar to those used in ponds)- again i may be wrong but as you guys have years of experience please make a suggestion (don't bother isn't a valid suggestion
)If it works great - if it doesn't then it's something learned
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mouldmaker
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doake wrote:Cheers Clarkey, although in fairness if i went that far i'd probably build a sunroom or conservatory on it.
But building a structural steel frame isn't going that far?
Weigh up the relative costs. I'm willing to bet it'll work out cheaper to infill than it will to prove a point.
I've worked on a few schemes that involved laying paving on steel framework, and on flat roofs, and the guiding principles are (a) It'll always cost more than you budget for, (b) don't do it if you can find another way, and © there's always another way.
Edited By mouldmaker on 1169560909
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doake
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- Location: Belfast
Maybe it would be cheaper, maybe it wouldn't. Access is a problem and the lighter it is to get where it needs to go the better, which is why i started with the plain deck idea.
It's not a case of proving a point, the way i view things is if there's a concept then find out if it can be done and if there are specific pitfalls figure out if they can be overcome without scrapping the idea completely and weigh up if it's worth it.
The block comes to about one and a half tonne over the area which is at a guess 100 to 120 kilos per square metre. Enough piers under it at the right spacing will hold that, it's then a case of enabling a form of damp prevention going down into the base from the patio causing rot and at the same time allowing it to drain.
Which leads me to what i mentioned earlier - using that concept and not building walls and infilling how could it work. LLL mentioned noise due to movement - could i go with a thin sand base and sand the block in as normal? Drainage - even if i manage to damp proof the base i'd need to drain the block. All manner of questions come up but i don't have the experience to answer them and i may not see some of them which is why i asked for help.
It's not a case of proving a point, the way i view things is if there's a concept then find out if it can be done and if there are specific pitfalls figure out if they can be overcome without scrapping the idea completely and weigh up if it's worth it.
The block comes to about one and a half tonne over the area which is at a guess 100 to 120 kilos per square metre. Enough piers under it at the right spacing will hold that, it's then a case of enabling a form of damp prevention going down into the base from the patio causing rot and at the same time allowing it to drain.
Which leads me to what i mentioned earlier - using that concept and not building walls and infilling how could it work. LLL mentioned noise due to movement - could i go with a thin sand base and sand the block in as normal? Drainage - even if i manage to damp proof the base i'd need to drain the block. All manner of questions come up but i don't have the experience to answer them and i may not see some of them which is why i asked for help.
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lutonlagerlout
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we call ,what you are trying to do, "p**sing in the wind" you are going against current thinking
why do you want block paving?
is it for a grippy surface?
if that is the case why not ply it out like you said and get ronacrete to recommend someone who will resin bond gravel to your ply surface
this finish is only 3mm thick and you will get a granular finish
TBH when we build one golden rule is that masonry should NEVER bear on timber,because timber flexes ,masonry doesnt
what you have described doing to my mind will not look well and there is a good chance of the timber failing due to constant exposure to moisture
good luck
LLL
why do you want block paving?
is it for a grippy surface?
if that is the case why not ply it out like you said and get ronacrete to recommend someone who will resin bond gravel to your ply surface
this finish is only 3mm thick and you will get a granular finish
TBH when we build one golden rule is that masonry should NEVER bear on timber,because timber flexes ,masonry doesnt
what you have described doing to my mind will not look well and there is a good chance of the timber failing due to constant exposure to moisture
good luck
LLL
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doake
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- Location: Belfast
If no-one went against current thinking over the years we'd be in the dark ages. Therefore i reckon i'll have to risk getting a bit wet.
As i said i have the block sitting doing nothing and it was an idea. I don't mind a deck but if this can be done i'm willing to give it a go.
You're right the timber may fail - question is how do i minimise that problem? Indeed don't build masonry on wood but these are small blocks which can flex and won't be mortared in place with no other structure on top.
My point the whole way through this thread is how could it work? I get told it won't work and that i shouldn't do it, but instead of thinking how it won't work, think how it could.
If it doesn't work what have i lost? A bit of time and some money.
Worst case the whole thing get's ripped out. Least worst case, i lift the block and deck the structure.
As i said i have the block sitting doing nothing and it was an idea. I don't mind a deck but if this can be done i'm willing to give it a go.
You're right the timber may fail - question is how do i minimise that problem? Indeed don't build masonry on wood but these are small blocks which can flex and won't be mortared in place with no other structure on top.
My point the whole way through this thread is how could it work? I get told it won't work and that i shouldn't do it, but instead of thinking how it won't work, think how it could.
If it doesn't work what have i lost? A bit of time and some money.
Worst case the whole thing get's ripped out. Least worst case, i lift the block and deck the structure.
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lutonlagerlout
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i agree with you doake, in that you have to try something new to invent new things,
but the masonry on timber thing was tried from the middle ages on and has failed spectacularly
look at all those old buildings with flying gables that are skew wiff
if you retain the blocks with say 4 " tanalised path edgings and the house wall the other side it may work
i suppose it is because it would be quicker for me to dig a little footing and build a wall that i ver that way
last saturday i did a footing ,concreted it and built a retaining wall with 300 bricks in it by 1 o'clock,just me and a lad .
so for me this works better
if you are confident with timber and fixing it go for it
bon chance!
LLL
but the masonry on timber thing was tried from the middle ages on and has failed spectacularly
look at all those old buildings with flying gables that are skew wiff
if you retain the blocks with say 4 " tanalised path edgings and the house wall the other side it may work
i suppose it is because it would be quicker for me to dig a little footing and build a wall that i ver that way
last saturday i did a footing ,concreted it and built a retaining wall with 300 bricks in it by 1 o'clock,just me and a lad .
so for me this works better
if you are confident with timber and fixing it go for it
bon chance!
LLL
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Stuarty
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- Joined: Sat Mar 18, 2006 7:35 pm
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I dont agree that what your doing is the way to go, but ill give you a few ideas for it.
Id concrete 4x4s into the old base, 18 - 24 inches deep. Id then make the frame, as you would with a deck, keeping the joists about 400 apart. Id use 5x2's. Once your happy with the framework, you can put some boards of ply down, but you will need to waterproof it. Once the framework and the platform is constructed and waterproof you could start to lay the slabs. Dont lay the directly on the board, dont lay them on sand either. Lay them on Caro Supports. If the slabs ever need to be lifted to gain access to the platform or frame its easier to lift this than slabs and daft amounts of sand. They also let the water flow under the slabs, rather than the water sitting in the sand. Make sure you put a run on the platform to shed water.
I think thats about it i think
Id concrete 4x4s into the old base, 18 - 24 inches deep. Id then make the frame, as you would with a deck, keeping the joists about 400 apart. Id use 5x2's. Once your happy with the framework, you can put some boards of ply down, but you will need to waterproof it. Once the framework and the platform is constructed and waterproof you could start to lay the slabs. Dont lay the directly on the board, dont lay them on sand either. Lay them on Caro Supports. If the slabs ever need to be lifted to gain access to the platform or frame its easier to lift this than slabs and daft amounts of sand. They also let the water flow under the slabs, rather than the water sitting in the sand. Make sure you put a run on the platform to shed water.
I think thats about it i think