For a Refreshing Change!

Decking (and all to do with) ....

A lot of requests have come to me regarding Decking, and a lot of questions related to it as well.  It does seem that a lot of people believe its cheaper, quicker and easier to choose decks instead of hard stone patios. - Hopefully, this page will sort things out for most of you, giving the 'Pros & Cons' of decking in laymans terms!


Okay, lets keep things very simple here.  Normal everyday decking is simply pieces of softwood planks and rafters and will rot if not treated - the same as your wooden fence or shed.  The difference with your fence and shed is you will not be walking on them, hence you will not be wearing any paint or treatment away with your feet (unless your spiderman!).

Decking obviously gets walked on, so will wear away any 'painted on' treatment - no matter how good the manufacturers say it is!

The answer  to good wood preservation lies with  'Pressure Treatment'.  As the name implies, it is a treatment for wood that is put in by means of pressure, not just a paintbrush and gravity. Imagine having a few tons of wooden planks inside a giant room with an airtight door. All the air in the room is sucked out (like sucking an open plastic bottle) at great pressures!  When the air is sucked out of the room it is also sucked out of the wood (like sucking a wet sponge).

The wood is then sprayed from overhead booms with a treatment, then the air is let back into the room.  As all that air tries to get back into the wood - it sucks the sprayed wet treatment in deeply with the action - that (in a nutshell) is pressure treatment, but it doesn't end there!

There's no point in going through all this if the treatment you are using is no good.  Many large DIY warehouses offer cheap 'pressure treated' decking to entice customers to buy.  But most of this treatment is no more than coloured water and will not extend the life of a raw untreated timber at all - it just 'looks' a pretty colour!

The word to look for is "Tanalised" or "Tanalized" or a trade name "Tanalith".  All these are basicly elements of Copper, Zinc, Cionide and other ingredients, designed to combat all the things that want to destroy a piece of wood i.e; Dampness, Mould, Fungus, and Insect Attack. If it dont say Tanalised on the product description, then it aint!  I have had a small piece of wooden batton that was accidentaly left under a footpath in my garden, built over 20 years ago, in a heavy clay that floods twice a year, yet the batton is as good as new - it really is that good a treatment.

TYPES OF DECKING  (Open a can of worms here...)

Again, to simplify:

1 - Regular softwood Un-Treated and Raw  = The cheapest

2 - Regular Softwood 'Pressure Treated" & "Tanalised" = May just be coloured water - ASK!

3 - Hardwood 'Foreign' = More Expensive than softwood but not recommended!

4 - Hardwood 'UK Grown' = The most expensive 'Real Wood' option.

5 - Non Wooden = A variety available from Resin to Plastic and beyond = Can be expensive!

Items 1 & 2 above, are covered in the treatment description in the previous paragraph, as they are simply 'Softwoods' and need treating.

Item 3 should be avoided if you are constructing a deck in the UK.  These beautiful looking decking planks and components have a natural bronze to red colour and really do look cool - but it is all grown in hotter countries and comes from Ramin, Mahogony, and any other tree name the supplier makes up!  This wood, and the tree it came from, never saw temperatures below 10o, and certainly no frosts or snow!  If you use this type of deck it will look really fantasic - until you get a frost or snow.  The wood will crack, distort, splinter, warp, shrink and virtually any other movement you can think of, simply because the wood has never had to endure UK weather or contract due to the cold ever in its life. Avoid this one!

Item 4, Hardwood UK - if you really want wood and you can afford it, this is the best.  Made from either Teak, Cedar or Oak (there are others), they just require a light oil every autumn to keep them in top shape and will certainly outlive the softwood types.  This hardwood UK type should have a 'Certificate of Conformity' to let you know that its a genuine grown in the UK product - Dont buy it if you are not sure, incase they are fobbing you off with the foreign one!

And lastly, item 5, the non-wooden one's.  The first of these appeared a few years ago now, and were really poor in construction and longevity.  There are now some really excellent non-wood decking options available, and do suit the 'modern' garden more.  There are even decking planks that are made from high quality resin extrusion and are made to look like wood, or granite stone, or even grass!  The grass is usually a piece of artificial grass that has been fixed into a wide slot of the decking plank, these are very good for steps as they give a non-slip property.  You can get the sparkly non-slip gritty strips, that are the proper non-slip stuff, and all manner of clips, screws, carcassing timbers and ballustrade all made from non-rot resin materials.  Decking has come of age!

Where and how big?

Where you put it is usually a bit easy! - Close to the house is ideal and designed so when your guests are sitting at a table on it, you are not going to walk into them constantly with trays of food or drinks.

Look at your doors out onto the deck and work out how big the table and all the chairs will be? Then imagine walking out to the table with a tray of something - can you get right round the table?  If you can, then it's the right size of deck, if not, back to the drawing board!

Shapes of decks can come in as many shapes as your imagination will allow.  But if you are going for a complicated shape, you will have a lot of work trying to fit straight boards into a circle or other rounded shape, also there will be numerous more cuts, more waste, more time and of course more expense.  Try to keep the shape simple and 'useable'.

Drains and other areas that cannot be normally covered, can be covered with a deck!  Likewise, any patio made of stone cannot come right up to the actual doorstep due to the damp course of the house - again, you can with a deck.

Drains can be covered with a deck but you must be sure to make a 'trapdoor' that lifts up to get access to the drains - if you dont, you will have a major headache and deck destruction getting to them should the need arise.

Decks can be built higher than the damp course of the house as it has large areas (gaps) in between the timbers.  This allows for ventilation and so, can dry out quite quickly.  This is very handy as you will virtually eliminate that great big six, ten or even twelve inch step down onto the normal patio height.


Apart from the quality of the deck boards (the bits you walk on), and all other timber used on your deck, some simple things to avoid during construction is always good to know.

The first is "don't skimp on materials"!

If you only get 50 deck boards instead of the required 53, your gaps are going to be massive and far too big in between the top boards, not to mention dangerous.  Likewise, the supporting beams that lay under the top boards also need to be a bit chunky to be strong, and should be spaced at roughly 16 inch intervals - this means your top deck boards will only ever have a 16 inch length with nothing under them - this is the specification for a normal thickness of board.  Go with less support beams means a greater gap well over 16 inches, and this means you have just turned your deck into a giant springboard!  The danger of breaking deck boards will also increase.

Try to go for nice chunky 4" x 4" timber legs for your deck.  These are the first to go into the ground, and well concreted as well.  Go into the ground at least 18 inches deep, with at least three good buckets of wet cement and ballast for a really good hold.  Foundations are everything and keep things rock steady.

Get galvanised nuts, bolts and washers and proper coated deck screws as well.  You will see shedloads of cheap alternatives  when you go shopping for your bits and pieces for the deck - dont be tempted - unless you only want your deck to last for a handful of years?

Even the timber parts that are not seen (everything under the deck top boards) should still be 'Tanalized' - more so, as they are not seen and you dont want these rotting whilst hidden from view!

Get your shopping list together ....

 By now, you should have your nice plan scribbled on a sheet of paper...YES?

So, you need to work out a materials list for your deck.  You have two options, either take your sketch to the local decking supply centre and say "what do I need?" or work out yourself what you want, so you can shop around a bit for the best prices etc.

To simplify your sketch: assuming it is a square shape (or rectangle), you will have one chunky four inch square tanalised foot, cemented 18 inches into the ground to each corner and at least two somewhere near the centre, spaced out so no two feet are within 8 to 10 feet of each other.  If you have more than 10 feet between the legs, you need to add more legs, spaced out until you have the correct amount.  These legs are best concreted in when the basic frame is fitted - this way, there is no "Ohh! the legs an inch out!" being shouted by you or your assistant. Go ahead and dig out the holes roughly where they need to go, OR if you have really thick concrete that is not all cracked up, you can fit the legs with a rubber boot and let it just sit on the concrete.  You can do this with most of the legs if you wish, just try to concrete a centre one and maybe two furthest corners - this ensures it will not 'rock' too much.

The frame (carcassing) needs to be worked out now.

Ok, the timber should be 4 x 2 minimum, but if your deck needs raising higher, and you have the finances, go for 6 x 2.  These chunky timbers should make a frame that goes all the way around the edges - literally a frame, just like a picture frame.  This frame then needs to be filled in with a grid of 16 inch gaps.  This can all sound confusing, so here is a simple image that shows this 'grid' that lays under the top deck boards :


 As you can see above, the darker colour is the support carcassing with the 16 inch gaps where the deck boards actually 'bridge' those gaps.  It is important to work this out so the deck top boards run away from the house as in this illustration.  Although decks can be level, its still a good idea to have a slight slope away from the house to take the water away after a heavy shower - plus, it will dry out quicker if the water can run away.

This carcassing frame will be screwed together using your treated quality, non rusting screws, and then when all done, will be itself fitted to the four inch legs by galvanised bolts.

Then have some handy bits of brick or something that can take the weight of the finished frame - these will be used as packing to adjust the whole thing up or down, whilst you then set those fitted legs into the wet cement and ballast mix. Dont forget to use that spirit level or the wine glasses may slide off the table!  Leave it for a day and there you have your finished framework that is steady and fitted to the cemented legs.

Laying the deck boards should be a little bit fussy, as these are the bits you will be looking at every time you look out the window.  Having scrapes and holes all over the place will look ugly, so treat the surface top of the boards with a bit of care, not only when you lay them, but when they are stacked in the garden as well!

Use something thats no more than 5mm thick as a spacer in between all top boards - you really must maintain the same gap throughout the whole top area.  Once you screw a board in two ends, you can take out the spacers and use on the next boards.  Try to make all screws roughly in the same place on every board - if not, you will be looking at an ugly wonky line of screws, and wished you did it right!

The last board will be the one that may need cutting down or making a slither to fit exactly in the space thats left - or, if you think ahead, you can very very slightly adjust the last 10 or so boards so it all fits in place - try not to go over that 5mm gap though - it really will look too big!

To finish up this very basic deck page, and for you to finish the deck - remember that kids or the elderly may use your deck, so be fussy with regard to splinters to the edges.  If any knots seem to raise out of the top planks after a hot bit of sunshine, phone the supplier and ask them if they will change it (most do if it is only a couple of boards).

Deck or Patio?

The most common question always asked when giving quotations ... whats the cheapest, Deck or patio?

It is not a simple answer!  If I ask you "How much is a pair of shoes?", what would your answer be?

If you had mid priced stone patio slabs, all laid onto a proper base material and not skimping on thickness anywhere, and you had a tanalised deck installed, the cost would be very similar.  Put simply, the deck carcassing and the labour to cut virtually every bit of timber, the holes for support legs, all the nuts, bolts, screws, washers and other bits and pieces all mount up.

A tanalised deck can actually work out more expensive than a stone patio once you get over twenty five or so square metres in size.  There is no simple answer as the amount of pros and cons to each are numerous.

Just remember that a stone patio will last a lot longer with much less maintenance, but a deck will need annual treatments to keep from rotting / to look it's best.

There is another option where you can have a mix.  A shaped stone patio that blends in with a shaped deck area.  This will give you the option to reduce the step out from the house, but have a harder wearing area for those scraping tables and chairs.  Below is an image of an installation done a few years ago using a circular patio with the deck cut to fit.

Enjoy your deck!

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