Paving

This post was written around 2009 and goes into technical detail on paving

Bradstone Aumtumn Bronze

It's difficult trying to compress everything I know onto a a couple of posts, so if there are any questions get in touch, that's what this blog is for. Ultimately I have found that with a reasonable amount of prep work you can avoid major issues and with a lot more prep work you can come away with a fantastic job.

These are composite slabs by Bradstone in autumn bronze. They look much better than the pics, as far as I am concerned most composites do look very good but when considering natural stone there really is only one that stands out. York stone. It looks fantastic and the reclaimed flags have a beautiful weathered look about them. York stone is incredibly hard wearing. I could put some pictures up but pictures generally don't do them justice. I could go on and on about york stone but if you have an appreciation for stone flags you know how gorgeous york stone is, there is just something about them, you really need to be in close physical proximity to get the real beauty of york stone.

Reclaimed York Stone

But these are composites and they look good, nowhere near as good as york stone but it should be noted that a beautiful finish isn't just in expensive flags, the beauty is also in a perfect finish. Remember to use a good sealer and when you need to reseal the flags don't forget to clear all the old finish off the face off the flags otherwise they new seal will not look even.

Considering the overall finish this is a great job, it looks great and will last years but when working with riven flags always be careful to make sure that any flags that are exceptionally riven don't end up in weak points, such as by the front door! ( Pvcu doors and windows don't look great)

Puddle

This area ended up being covered by the portico so this problem resolved itself but it is very important to make sure that slabs which are exceptionally riven don't end up being placed in key areas.

As far as sourcing slabs, its wise not to turn your nose up at manufactured stone, there are companies who are very established at making good composites, they can be used anywhere, if the sub base has been prepared specifically then you could quite easily drive a tank over these things, well maybe not a tank but most certainly heavy vehicles. Its all in the sub base and i will do a post on that later.

The slabs will be found at most builders merchants. The likes of Selco carry these but no natural stone and Travis Perkins do a good range of natural stone. Specialist places such as Rock Unique down in Kent are very good but unless your after something very niche your first stop should be Travis Perkins for natural stone. The composites will all come in a standard thickness and natural stone wont, generally the rule of thumb with natural stone is to put the face with the greatest width sunny side up (that's the way its supposed to be) Sandstone from India can sometimes be refereed to as Indian York Stone but i don't think it looks similar.

Another reason to use composites is that they come will all manner of features, for example the circle squaring kit. This can be a great feature when combined with good quality fencing and some stone bricks for a wall. Its always a good idea to keep your eye out when on site for natural materials that can be reused rather stuck in the skip to fill a landfill somewhere. It is very difficult to cut a natural stone slab, well its not difficult to cut it but it is very difficult to get a smooth natural edge.

You will need gloves to handle these slabs and be careful how they are stacked on site, these should never be stacked in a way that a slight knock can bring down 7 or 8 slabs propped up against 1, its not big or clever! Site safety should always be paramount and not just for people working and possibly living on the site but also for break ins.

So, if you are thinking of having a paved area then you will most likely follow this plan of action;

1. Investigate: Look at different designs, theres lots of info on the net and in manufactures literature.
2. Place order
3. Prepare sub base, I will do a post on this but its a vast topic. Generally its only wise to get the flags in as close as possible to the time they need to be aid - no pint cluttering up a site.
4. Wheelbarrow slabs from site entry to where the flags will be placed, you will need gloves and a good wheelbarrow. Store flags appropriately.

In summary,
Its absolutely unacceptable for there to be any puddles on paving. Riven slabs may cause very slight puddling but not for longer than about 20 minutes after the rainfall has ceased.

Same puddle, different angle :-)

Cement for concrete basics

Well soon enough im going to be writing about my favourite part of the build. I especially love the groundworks. Before then you need to know a bit about cement and concrete - so everything you will need to know about cement and concrete to prepare you for groundworks.

A brief history of cement;

In 1820 Joseph Aspdin discovered that when he ground up the limestone and clay and heated it, then added water to the resulting ground up powder, he found that it hardened. He decided to call it Portland Cement because he was a business minded guy and the majority of the building work at that time was done using a type of stone quarried on the Isle of Portland which is off the British coast. The accepted view is that his mix looked like portland stone but im doubtful.

Applications in order of importance as defined by me

To make a good general purpose concrete mix;
one shovel of cement to two shovels of sharp sand to three shovels of max 20mm aggregate.

To make a good paving concrete mix;
one shovel of cement to one and a half shovels of sharp sand to two and a half shovels of max 20mm aggregate.

To make a good foundation concrete mix;
one shovel of cement to two and half shovels of sharp sand to three and half shovels of max 20mm aggregate.

If your using ballast, its a different story. Ballast is an all in mix of sharp sand and aggregate. It is more common down south then it is up north. Im not that keen on ballast - its never the same, each ton bag is always different plus theres never enough 20mm aggregate. Rubbish because your never assured of a consistent strength of concrete, but used because its convenient - a factor which has an amazing ability to corrode good building practise, a factor which is driving most building innovation. . .Ask your project manager if he uses ballast. If he does think twice about hiring him. If he mentions ready mix...thats another blog.

In all of the mixes above, dont put too much water in the mix - water will reduce the strength, just use enough water to make it possible to place it and to compact it.

Since I'm writing of concrete its only fair to add a bit about admixes;

SBR: Has a lot of benefits main benefits are when doing a screed that's going to end up as a tiled floor - the SBR in the concrete that is the screed, will become a tiny bit flexible, so when the underfloorheating goes in under the tiles its just better because the screed will flex a tiny amount when the UFH is turned on and it wont breakup. I usually use SBR its inexpensive and has many benefits.

Dustproofer and Hardener: Not that important its basically used to seal a concrete floor, you end up with a hard wearing non dusty surface. I suppose it is cheaper than concrete paint, which costs a fortune. If you need to finish a floor where the visual aspect is not important use this instead of paint. Plus with concrete paint technically you shouldn't use it till the concrete floor has been down for 6 months minimum.

Waterproofer: I wouldnt leave it to an admix to waterproof concrete, if its going in a render its a different story.

So of the above which brands to buy, well they are all pretty much of the same, the main distinction being branded or undranded, I personally would go for the Sealocrete products and as far as PVA goes buy Unibond 10litre stuff then water it down - works out far less expensive thant the 2.5litre unbranded stuff. As far as the waterproofer, i will discuss below. The real major issue / screw up that will occur when on site, the absolute main reason why failure occurs is because some bright spark isn't putting the right amount of admix into the mix. That's the main reason why the admix will fail to do its magic not because of brand.

So which waterproofer? Sika is in a class of its own, far far far better than any other waterproofing product on the market. And its a lot more expensive, unless you know where to buy - If you need it for a big job, go Travis Perkins and buy the 25litre ones - will set you back about 100quid but well worth it.

I should mention that not all admixes work well together. For example, lime makes a render more workable, sika makes a render waterproof but if you are adding lime to a Sika render it will have a negative effect on the waterproofing abilities of the render. And sika at 100 quid/25 litres you dont want the waterproofing capabilities diminshed in any way. So dont get into the habit of throwing everything in to the mix - always check the data sheet. Or call the tech helpline.

Im gonna mention all the different types of cement; to be honest the important stuff is above but here we go

General purpose cement - Used for most applications
Premium cement - Lighter colour and has improved workability offers slight protection from freeze-thaw attack
Rapid cement - High strength NOT early setting!
Fastset cement - Sets hard within an hour, its suitable for fixing posts
White cement - Used for decorative purposes but also has high strenght
Sulfate cement - Use this below damp proof course where sulphates are present in the soil

Stick with general purpose cement.

This blog is getting really big and im probably at risk of losing your attention, thats why i wrote in order of importance but since we are talking of concrete i must put in a note about A142 mesh.

Its a mesh that reinforces foundations, ill post more on this when i discuss the foundations.