I'm not overly familiar with screened pool enclosures - we don't have much call for them here in soggy Warrington (England), unlike you lucky sods in Florida-land, but I'll see if I can help...

Given that this is likely to be a very wet environment, I reckon you need to opt for a rigid construction, which means laying the pavers on a bed of mortar over the top of the existing concrete base. In theory, you could use a flexible construction, but if you did, I'd strongly recommend it be sealed to prevent saturation of the bedding layer.

The aluminium rail - I assume this is some sort of guard rail attached to the existing concrete surface via anchor bolts. There are two ways of dealing with this. If the height of the rail is critical (ie, it must be a certain height above floor level) then it could be detached, set aside while the area is re-paved, and then fastened to the new surfacing once the bedding/jointing has cured. Alternatively, you could pave around the downstands and fill in any gaps with the mortar used for jointing.

Drainage - water will run over the surface of the paving, just as it runs over the concrete deck at the moment, so, if you match the current falls, any surface water will drain as it did before, into the open channel you mention. Given that the drop to the channel will be increased by the thickness of the paver plus the bedding, then it may be worth elevating the existing channel, or installing a new one at a higher level, but, without knowing the exact layout or the type of pavers you propose using, it's not possible to state which would be the best option.

Are you diy-ing this or bringing in a contractor?

When it comes to finding a local contractor, try the ICPI site - they're the trade body for what you call Paver Installers in the States and should be able to put you on to someone in Florida-land. But, if you get really stuck, I know a really good paving expert who could be flown out to Florida from Warrington quite cheaply and is happy working for beer and bacon butties (Oops! Sandwiches, to you)

Anyway, 300x300 is the threshold of what we term as paving blocks and what is known as 'small element paving'. These start at 300x300, then 400x400 (what's that: about 16", I think) and then 450x450 (18"x18" ).

This small element paving is only really taking off in the UK/RoI over the last 10 years or so, but we predict it will become more and more popular, especially for civil and commercial schemes, as it offers all the benefits of an elemental paving at a cost below that of decorative block paving, and offers fast installation, too.

Properly laid, there's no problem of stability or interlock with small element paving. Some of the leading research into the subject has been carried out under the auspices of Prof. John Knapton and you can read some of his findings on the SEPT site.

If you follow your preferred option of replacing the cracked/dropping concrete with pavers, then the 'membrane' you need is known in the UK as a Drainage Composite - you can read more about them on the Fin Drain page of this site, but I've no idea where you would find them in the US. These composites collect any water that finds its way beneath the paving and channel it to a convenient disposal point.

However, given the scale of the work, I think it may well be worth asking a local contractor to inspect the site and give you advice on the best way to proceed. Builkding methods and materiuals are vastly different in the US and what seems like a good idea to me may not be feasible, or even legal, in your country.

there's 2 options - either use a decent sealant over the entire driveway, which will seal in all the sand, or take out a second mortgage and buy a pack of Geofix and use that to seal the block joints that are right on the edge.

Geofix is a polymeric sand, ie, it's coated with a special goo that sets when exposed to the air. We find it's never quite as good as the manufacturers (recently bought out by FEB) would have you believe, but it should be ok for this sort of work.

It's 12 months or more since I last had to buy any, but I reckon it's around 40 quid for a 10Kg pack.

However, a decent sealant will cost you maybe 1.25 quid per m², but you do get the added benefit of protecting all your paving, not just the jointing sand, so you have to weight-up what suits you best.

If you contact the Resiblock site and tell them I sent you, they'll send you a 250ml sample that you can test out in a discreet corner of your blockwork to ensure it doesn't 'varnish' your paving.

In my opinion Resiblock 22 is probably the best block paving sealant on the market, anywhere, and it's not often I unreservedly endorse a product.

Have you checked the coverage rate? Personally, I'd be very reluctant to use any polymeric sand on a block paved driveway unless there were extenuating circumstances, such as a lot of scour or a steep slope. Why do you think it would be an advantage on your driveway? I'd be interested to know.

Get the rep out, and see what s/he has to say - you might be able to blag a free sample and get a trade discount.

And ask them what happened to all the bumpf they promised to send to me last year when they were on the 'phone for 90 minutes extolling the manifold virtues of GeoFix!

If you really want to avoid using concrete, then one of the nailed-in edging restraints would also be suitable, provided nothing heavier than a car will be used on the driveway.

HTH

I'd lay them on a 10:1 sand:cement bed and just haunch them enough to keep the line in place, Mike.

Cutting for the curves won't be as complicated as you imagine. What sort of radius do you envisage, and what type of block will you be using? If any cutting is needed, I will be able to tell you how much to cut.

I'm not sure what you mean by the sub-base for a one block strip - if this is just a mowing strip, then it's laid on the 10:1 concrete bedding; there is no sub-base required.

For the 10:1 mix, use a grit sand - see the Concrete page for fuller info. You can substitute 5 parts gravel for 5 parts grit sand, if you prefer. 10:1 is usually fine, as it's only to hold the blocks in places, not to contain a trafficked pavement or anything like that, but, if you wanted, you can up the strength to 6:1.

For a 4m radius, you shouldn't need to trim the blocks at all.....

...as there is only a 5mm gap between adjacent blocks.

If you can mark the origin of the 4m arc, it's much easier to accurately lay out the arc. See the example on the Steps for Block Paving page.

Good luck!

If you use the blocks 200mm wide, it still wont make much difference on a 4m radius. You will find it even easier to create a sweet curve than it would be laying the blocks 100mm wide, as each unit is narrower relative to the arc.

BS 7533-3:1997 stipulates a bedding layer of 35-50mm, and we know from experience that anything over 60mm is terribly prone to channellisation (rutting). Your contractor should make up the levels with lean-mix or DTp1, not with extra sand.

You can try their website for further info, but it's essential that the 'Superior' is not applied as it will 'upset' the "22" when that comes to be applied. There's no-one in the Resiblock Office now until Monday, but, if you want, I can give you their 'phone number and they will tell you where your nearest stockist is located.

Acid washing only works on cement stains, such as those cuased by spilt mortar or concrete. It won't work on efflorescence and it won't work on crushed sand. Also, you need to be very careful with acid washing as it can alter the colouring of the paving.

The use of a rubber mat on the plate of a vibrating plate compactor is not essential and many contractors prefer not to use one for residential driveway/patio work with concrete pavers. The are a good idea with clay pavers, or with concrete pavers that have no spacer lugs, but, for the vast majority of British and Irish concrete paving blocks, they are a waste of time and money.

These marks could be crushed sand, but, if they are, they should be able to be shifted by rubbing with a wire brush. I'd try that before resorting to an acid wash.

And finally, yes: the jointing sand is a specially selected sand of specific grain sizes. The full grading envelope is given on the Pointing and Jointing page. Your contractor should be using sand that comes in bags marked as "Jointing Sand" or "Kiln Dried sand for block paving" and not just using any old sand that's lying around.

So, put away your matchbox.

Just lay the edges where you want them, and then cut the body blocks to fit. If you want an exact dimension, it can be calculated if you know the block you plan to use and the pattern, but I can more or less guarantee that, even if you set it out with a laser level, an Earth Station and GPS, it would still end up being 5-10mm out one way or t'other!

That's the wonder of block paving.

That's why I say always get at least 3 prices for any residential building work.

Last I heard, it was finished 2 days ahead of schedule looking, and I quote, "***king brilliant"

Keep us informed on your progress (or lack of it!)

You could do the 'Friday afternoon' cut, which involves smacking the edging in the middle with a lump hammer, giving a wonderfully organic-looking raggedy edge to the cut on the top face, or, you could go for the 'professional' cut, which means using a power saw or nangle grinder to nick the top face to a depth of around 20mm, and then smacking the edging in the middle with a lump hammer - this gives a nice, neat edge to the cut.

Experience - it cannot be bought!

1 - getting a contractor willing to supply and lay 4m of bitmac is damn near impossible, even if it's 5m wide giving a total area of 20m².

2 - Cost - The set-up costs for bitmac are considerable - bringing in a roller, the insulated delivert wagon, the tarps, the firebox, the special laying gang, all the tools etc, costs the same whether you're laying 20m² or 200m², and so bitmac becomes very expensive in small quantities.

3 - Block paving can be sealed to prevent erosions of jointing sand and bedding by water, even from inundation. And although quality sealants aren't particularly cheap (reckon on 2-3 quid per m²) it's still a lot cheaper than having a small patch of bitmac laid.

4 - Aesthetics - That 4m bitmac strip is always going to look like a council-installed crossing apron over a service strip, even though it's your own property.

If you're really, really worried about the possibility of inundation, then you could consider a rigid form of block paving, rather than the usual flexible construction.

Have you had any costings provided? It's worth asking a reputable local contractor to give you prices for all blocks and the blocks/bitmac split, just so you can see the effect of having a small patch of bitmac laid to a residential driveway.

Keep us informed about your progress - or lack of it!

Try and dump the sand as close as poss to the working area. It's ok to dump it at the edge of the proposed driveway, and then feed from it as you lay your edge courses and then establish your screeded bedding. Any excess will have to be moved off the working area, of course, but it's easier to barrow, say, 1T of excess off the working area, than barrow 7.5T into the working area.

Alternatively, you could get the wagon driver to split the delivery, dropping 4T or so on the working area and the remainder somewhere out of the way.

Once the blocks are laid, they protect the bedding from the worst of any rain, but, if there was a real, torrential downpour, that might cause some problems if it is allowed to saturate the bedding and the sub-base isn't capable of draining it quickly enough.

You should always allow the bedding 24 hours to drain itself before final compaction of the blocks, otherwise the bed can become 'fluid' and pump its way up through the joints, and the jointing sand itself is a bugger to get settled into the joints.

The best protection you can give your paving is to get the ground covered with blocks as quickly as possible, get the cutting-in done, and get it sanded and compacted ASAP. Once all that's done, it can look after itself.

Don't get stressed - re-lay the blocks and then use the blade of a trowel to adjust the spacing once you've got them all back in place, trying to even out the joint width. As long as you keep the joints to 6mm or less, you'll be ok, as the jointing sand will take up any slack and hold everything tight.

These are concrete blocks, aren't they?

Remember to send me a pic when you're done!

Can't wait to see the piccies, Darren, and add you to the Hall of Fame!

Darren's photos can now be viewed on the Block Paving DIYers' page.

As for the sealing, you need to leave the sand jointing for 6 weeks to let it settle, and then top it up, which puts us in to mid-November, when the ground is hardly ever dry. So, I'd be tempted to leave the sealant until next Spring, say late March, when the sun has dried off the surface once again, and the efflorescence has dissipated.

If ordering direct from Resiblock, tell them I referred you and you'll get a decent price.

I'd try using a detergent and a spadeful of grit sand, and give the lot a good scrubbing with a stiff brush. Don't be tempted to use an acid-based cleaner at this stage, or it could discolour the section you're cleaning. If the detergent/sand mix doesn't work, I'd leave it until spring, as you may find that natural weathering removes the worst of the staining.

Have you thought about building a patio with the left-over blocks??

On flat sites, we would normally start at the base line and work from that, but on a sloping site, the base line, or a perpendicular, would be transferred to the bottom of the slope.

Always work from the paving that's just been laid, on not from the screeded bed.

Glad you like the site, and the DIY pics - send in some of your own and I'll upload them for you.

Well, if that's what the client wants, fairy nuff, but I think they could end up regretting their choice. It's going to end up looking 'bitty', but, until the whole pavement is laid, there's no easy way of giving them a visual indication of the finished results.

From a laying point of view, you will have to truly randomise the blocks. There's a temptation to lay, say, a brindle, then a brown, then another, then a brindle again, then a brown...and you end up with a pattern instead of a truly random mix. Best way is to get the labourer to load, say, 16 of each colour into a barrow, unload them at the working edge in a random fashion, creating, say, 3 stacks of 16 blocks, and then have the laying operative place the blocks 'as they come'. If you get 3 brindles together, leave them. This is the only way to get a truly mottled appearance.

Still, at the end of the laying work, you're going to have to stand back and survey the work, to see if there are any areas that stand out or look uneasy. Lift, randomise and re-lay as required until it looks as right as it's going to get, and then do the sand jointing. I'd add a few bob to the cost to cover this extra configuration.

Screeder bars and rails: - we make our own by buying aluminium box- or I-sections from a local supplier. Lightweight, very strong, and dead true.

If you want a professional system, have a look at Probst's stuff. It's the best kit in the world, bar none, and there's a link in the Tools section, or from the Screeding page.

The screed kit consists mostly of 75x25mm (approx) I-section or box-section ally that's used as the screeder bar and then 25x25mm box section or tubular ally or steel conduit for the trammel bars. The trammels are minimum 2m in length and max of 6m (but these have to be treated with respect to keep them from bending), while the screeder bars range from 600mm to 4m, with one 'beast' that is a 150x50 section and 7m long.

A mate of mine runs a double glazing business, so getting hold of ally section is no problem for us. He lets us have off-cuts for a pint and custom sections at cost.

When ordering the sand, ask for "Coarse grit sand suitable for laying block pavings" and the BM should be able to sort that out. The full name is often given as a "Zone 2 Class M washed coarse grit sand", but that would only befuddle the poor order clerks behind the desk!

Once the bed is levelled and screeded, it should be paved over asap. If you leave it overnight or longer, the local cats will shit in it,and it will be disturbed by wind, rain etc., so it should be topped-up and re-screeded just before laying the blocks.

Keep me informed of how you're getting on.

Getting the levels right where the blocks lie under the cill can be a bit tricky, but if you judge the bedding right, they will go in and you should be able to tap them down enough to consolidate the bedding. Once the cement content sets, that should be adequate.

How's it all looking? Any photos?

Dilute it, as it says on the pack, with 6 volumes of clean water, and stir it well. Douse the paving - you don't need to go to a lot of trouble making sure coverage is exactly even - spread through a rose on a watering can until the top of the blocks is wet, then move on to the next patch. Excess liquid will run off the surface of the blocks and find its way into the joints.

It takes an hour or so to dry, and you might notice a whitey-purple hue to the paving at first but, rest assured, this will disappear in the next 24 hours or so, leaving the blocks completely unaffected, but the sand jointing bonded together.

If you're still nervous, just treat an area of a couple of square metres in a discreet corner, leave it for a day or so, and see for yourself how it works out. Fret not - as long as the Keybond is properly diluted, it's almost impossible to balls it up.

It's your drive: you have to live with it, not me nor any other 'professional', so choose the pattern you want. I honestly believe a herringbone, particularly a longitudinal 45, presents the bricks in their best light on almost any driveway, but if you want basketweave, then you have basketweave.

The best method is to lay all the edge courses before laying the body blocks.

The answer is "buggerall", and if you try it, the free edges of your paving will scatter and the whole body of the paving will slip out of line. Don't do it - you'll only regret it!

1) any caveats about doing this

If you're using semi-circular planters of less than around 750mm dia, then you're better off using relatively short pieces for the soldier....

....around 125/100 length, rather than trying to do it with longer cut blocks, say 200/175. This is illustrated better on the Block Detailing page, where I look at different ways of laying a soldier around a circular manhole.

2) any suggestions about shortcuts for the arithmetic and techniques for making the minimum number of cuts,

3) any advice on the best ways to handle the problem that the natural rings of cuts will get perilously close to, or need to cut into, the soldier line?

Normally, the soldier line is maintained and the body of the paving cut to suit.

I guess I should lay the main path up to these areas, so I can see the lines the pattern in the main path is taking. Then cut the ring and bed it in concrete (with haunching inside). Then when dry, cut & fit the remaining piecings, then compact the whole path right up to the ring(?)

That sounds about right. If you soldier edges are taper cut, they act not unlike the stones of an arch, and so you can minimise the haunching concrete used or even use that awful Keyform edging restraint.

My apologies if this is covered on the website, but I couldn't find it if it was. As usual, grateful for your help. - Mike - (I can provide you with some 'before' pictures !!)

Oh, yes please - and some 'afters'

1 - mark/score the top face of the block. Hit the bolster hard enough to mark the block BUT NOT TO CRACK IT.

2 - do the same on the two sides, angling the bolster to create and undercut.

3 - repeat on the base of the block, joining the two 'lines' made on the sides of the block.

4 - turn block over so the face is at the top and strike with a single swift blow with the bolster. This should cause it to fracture along the lines you've scored.

You can lay the block on earth or on sand while you do this, as they hold the block steady and absorb/deaden the impact of the blow without reflecting it back into the block, as it the case if you rest it on a hard surface.

It's so much easier with a splitter - they're eejit-proof! (almost)  

If you can hang on until lunch time tomorrow (Tuesday) I'll upload a couple of pictures showing how the blocks are first undercut and then trimmed. It's 20 past midnight just now, and I don't think the miserable gits next door would be best pleased if I started cutting blocks at this time of night!

....Next Day......

Thankfully, the rain has held off for long enough to allow me to take a few photos in the back garden....

1 - Lay the block on its side, make sure it's stable and firm, and undercut it by striking on the side...

...sometimes, one good blow to one side will undercut the full width of the block, and other times you need to attack from both sides. As long as the section of block to be removed is undercut, that will be fine....

2 - Once the block has been successfully undercut, turn it face up to commence the trimming operation...

Use the hammer and pitcher/bolster to nibble off a bit at a time. Angle the tool into the block slightly when striking as this helps maintain the undercut....

....and use swift, sharp blows until you've trimmed back to the cut line.

...you can easily trim off chunks of around 25mm at a time, and then tidy the cut edge once you're there or thereabouts.

Done! I used a Pitcher (Pitching Chisel) rather than a bolster, but the procedure, and the results, should be the same.

It's great fun all this paving lark, innit?  

When we do hand-dig work, we expect each operative to excavate and load into a skip at least 3 cubic metres per day. A good gang of 3 men will easily excavate and load 3 skips per day, with roughly 4.5 m³ per skip. On a soft dig, such as sandy loam or cow-belly clay, we can double that.

Maybe it's all that digging that made me the man I am today - a knackered spine and a dodgy ticker!

Well, the pavement should slope so that the surface water is directed to a disposal point of one form or another, be it a gully, a linear drain or the public highway at the threshhold. So, the water runs across the paving, meets the kerb and then where does it go? Were you planning on draining onto the lawn? If so, can your lawn cope? How big is the area? What's the ground like in your garden?

It's not insurmountable, but if you can explain the falls and the drainage provisions, I'll be able to offer some solution, I'm sure.

[Height of kerb] - [Amount of Upstand] + [Depth of Bedding]

.... below paving level.

So, if you were using, say, a 200mm high Boot Kerb, with 125mm of upstand, then the sum would be...

200 - 125 + 100 = 175mm

ie, you'd need to dig a trench 175mm deep measured against the paving surface level.

Does that help?

Use a semi-dry mix; concrete with just enough water to make it damp. Not wet, not moist, just vaguely damp, so it just about clumps together when squeezed into a ball. Then, when you bed a kerb, it stays bedded, and doesn't 'float' or 'settle' when you come to lay the adjacent unit.

You could blind the bottom of the trench with sub-base material, but aim to be laying on between 75-100mm of concrete, if this is a retaining edge.

If you decide to smash up the flags/slabs, you can use a sledgehammer or a lumphammer, but it's a lot of work!

For the digging - it depends on the area and access. If you can get a mini-digger in, then so much the better; if not, then it's a job for the pick, the mattock and the spade - see the Tools page.

Option 1 results in wide joints which aren't critical on a pathway such as this but you could end us with a handful of blocks right on the sightline that are 'skew-whiff' and stand out like the proverbial thumb that met the lump hammer.

Option 2 will more or less bring about the same result as option 1, but with fewer skewed blocks.

Option 3 would seem to be the most logical but that outside edge course, against the grass, should be straight, assuming you've laid it to a taut string line, so any amendments to the alignement will look worse than the few skewed blocks in Options 1 and 2.

The best solution is the one you missed - option 4 - lever over the blocks on the internal soldier course, the one against the house, as it's all but impossible to get a sight line along there. Create the 'take-up' gap between the wall and the back edge of the soldier course and pack that full of jointing sand.

It's quite probably deviation in the wall that has resulted in the error in the setting out, so keep all the eror in one spot and you'll not be able to notice them.