Garden Decking Guide

With Summer ending, you may find that you have more time on your hands. So why not use this to your advantage and spruce up your garden ready for next year? With some garden decking you can really spruce up your garden.

Decking bases

Before choosing decking, you should consider where and how you’re planning to build it – Is it ground level on a concrete base? Or maybe you want it raised on posts. In this section I’ll explain the various ways to go about doing this.

Ground level decking

Planning to build your decking for just outside the door? Or perhaps you’re planning to use decking to complement a newly built gazebo- The base to your decking will be relatively easy, but what to chose as a base will depend on the ground you’re building it on.

Garden Decking Frame Joists

If you’re planning to build your deck on a hard surface, such as a concrete base, 95mm thick framing joists will be suitable. Due to the ground being hard and unlikely to sink, then you can be reassured that these timber joists will still create a durable deck.

For decking on softer ground, such as grass, we would recommend that you upgrade your framing joists to 145mm thick timber. This will prevent your deck completely sinking into the ground, this timber is also ideal for more heavy duty uses- Such as being built as an addition to a Log Cabin.

It is important to note if you are planning to do a ground level deck, precautions will have to be carried out for the timber to ensure the longevity of your deck and frame. It’s important to note that your timber shouldn’t directly touch the ground- Using slabs or concrete blocks will help prevent the timber from getting damp, using a damp proof membrane or Weed matting will help further protect the base of your deck.

Another step to consider is treating your base josts, you can use a range of timber treatments for this step including our Black Tar Timber Treatment. Treating the joists as well as your decking boards will contribute towards the lifetime of your deck.

Raised Garden Decking

Raised garden decking is another popular way to build a deck- It’s generally the ideal way to make use of limited space, along with being able to build a deck on uneven ground or on a slope. With a raised deck, more options are then presented to you such as building steps and balustrade sides to prevent any accidents from occuring.

The most common way to build a raised deck is using Timber Posts. So long as you are able to keep the post secure in the ground, you will be able to create a deck as high as you wish. If you are planning to use posts to raise your deck, it’s best to use 145mm thick timber for your base joists.

Timber Frame Base Pads

Or, if you are planning to have a slightly raised deck, allow me to introduce you to our Timber Frame Base Pads. These pads make the leveling your timber frame easy, with adjustable heights up to 150mm, they can hold up to a weight of 1400kg.

For the best results, we’d recommend that you place the pads on a paving slab or something of a similar shape. The 95mm thick framing joists will also be the best choice to pair with the base bads.

Garden Decking Kits

These kits have been pre-calculated to reduce the hassle of working out how many decking boards, screws and base joists are needed.

They’re often are available in a range of widths from 3m to 6m- These widths increase in 0.5m increments. Along with the widths theres also depths in 20cm increments, ranging from 2m up to 4m- Allowing you to build your deck to the size you need for your garden.

Decking Boards

Decking Kit Boards

Most retailers will offer their decking with a 19mm – 24mm thick boards. Because of this, we have decided to offer two thicknesses of our decking boards- 27mm and 31mm thick, both are thicker than standard in order to provide you with decking that will last. To choose which thickness you’d like, take into consideration the purpose for the deck, along with the footload it could have.

Along with our decking boards being thicker than standard- They are also tanalised and kiln dried. The tanalisation treatment may give the decking a green appearance, but this treatment is done to help prevent the timber rotting in damp weather. Although, we also recommend that you further treat the boards with a suitable treatment, such as decking oil, to help ensure the longevity of your new deck.

As the name suggests, kiln drying is a process of drying out the timber in a kiln to a moisture content that’s suitable for use in construction projects- Perfect for use with decking. Kiln dried timber also results in less cracking and warping in the timber, making these decking boards durable for many years of use.

Framing Options

We understand that there’s multiple ways to build a deck, whether it’s on soft ground, a concrete base or raised on posts. This is why we have given you the option of two base joist thicknesses- One of 95mm and the other for 145mm. The option you choose will depend on how you plan to install the decking.


Garden Decking Screws

Due to the timber being tanalised- It’s not recommended to use standard decking screws. Because of this, our team have selected an alternative screw that feature a wax coating, allowing you to install them quicker and with less effort. The framing screws have been chosen due to their large head- Known to be resistant to breakage.

The screws have been listed as an optional extra- To not pressure you into buying our screws. However, you can find the number of boxes needed by looking at the kit list on each product page if you wish to order your screws with us.

Decking Tiles

Subaya Decking Tiles

If you’re like me, a person who wants the cleanest looking result- Then our Garden Decking Tiles may be the solution. A great alternative to traditional decking boards, these tiles come in a variety of styles and materials to suit your decked area.

From Hardwood to Composite, these decking tiles will be perfect for our Gazebo’s and Log Cabin Verandas, when used appropriately these will really create a stunning finish to your Garden feature and/or structure.

Composite decking

Our Composite Decking range is the ideal solution to wet areas, due to the combination of 60% wood – 40% plastic for the composite material, they will never rot. The composite material is 100% recyclable, it also has some similar features to wood decking such as expansion and contraction- An important thing to consider during installation.

Checked Composite Decking

Decking – the usual method

I’ve been asked a lot recently about our garden decking and especially how it is installed and on what sort of base, so I thought a short guide maybe helpful to our customers.  Of course it’s also a plug about our products, our composite decking is proving very popular as are our decking tiles and decking boards.  Interestingly sales  for the composite decking is increasing month on month

Composite decking

Composite decking

As a quick guide I suggest the following, of course there are lots of ways of accomplishing the same thing but this, I hope, is a good guide or at least gives you a few pointers.


Like any project, planning is the most important part, it shouldn’t be overlooked, what’s the old saying?  The five ‘P’s’:  Planning Prevents Pi – –  Poor Performance!

So, first make a rough drawing of your design, laying out pieces of wood to mark the edge of the planned decking always helps me to visualise how it will look.  Decking board at right angles helps to draw your eye into the house, board’s parallel show off the width of the decking.

It’s a good idea to make a scale drawing and also add the house walls, openings, obstacles etc.  If you’re attaching the deck to your house always make sure that the attachment point is 150mm below the damp proof course.  Make sure as well, you allow access to inspection covers and importantly don’t block air vents.


Using your scale drawing calculate the area of the deck.  Divide the area of the deck by the size of the decking tiles you are using or the timber / composite decking planks.  Remember you will have to include spaces for expansion and drainage between planks, I tend to use 5mm as a guide.

If you need help calculating what is required please do contact us.

Ground Work

Decking is usually built on a framework supported by concrete footings.  It can either be simply placed at ‘ground level’ or if needed ‘raised’ using uprights.

First it’s a good idea to use pegs and string to set out the deck perimeter.  Clear all turf and vegetation and firm the ground if needed.  It’s a really good idea to lay weed inhibiting membrane down on the area at this point to stop any nasties coming through.

Decking Frame

The framework should be put on concrete foundations.  You could lay concrete for this but slabs are a lot easier.  Slabs would normally be placed in a grid pattern about 1400mm apart to allow for adequate support for the joists.  If you have bad drainage or poor soil condition consider using poured concrete in holes of at least 300mm square.  Use a spirit level and try to make sure the deck slopes (away from the house) roughly 10mm for every meter.

Create the outer frame of the deck with pressure treated, tanalised timber.  150mm x 50mm is ideal.  Where the timber touches the ground use a damp proof course membrane.  In our ‘ground level’ method these joists will simply be placed on the ground being supported by the concrete grid.  For the ‘raised’ method these will be supported by uprights, I recommend 90 – 100mm sq tanalised timber.

With the frame in place use at least 100mm screws and wood glue to fix it together.  If the decking is being attached to the house make sure you add plenty of spacers to allow for a drainage gap.  Stainless steel washers are excellent for this.  Next you will infill the outer frame with joists spaced at 400mm intervals.  These should be at right angles to the finished decking tiles or boards.  You could use off cuts of timber to create noggins in between the joists for extra strength.

Laying the Decking

Once your framework is complete and totally rigid you can start laying your decking boards or tiles.  Lay about 6 boards at a time, I have already mentioned an expansion gap and to accomplish this evenly I tend to use a decking screw as a spacer (remove after fixing).

A few notes on fixing your decking boards:

  • Always use stainless steel or galvanised screws, there’s nothing worse than seeing rusty screw heads and stained decking boards.
  • Always pre-drill your screw holes, without this you run a risk of splitting the timber.
  • Screw the end of the boards first and then to every joist.
  • If the decking boards are wider than the deck you must make sure you stagger the boards and that joints are over a joist.

Raised Decks

Raised decks are slightly trickier and need a little bit more thought.  As I mentioned you will be using uprights of about 100mm square.  These will be held in place using metal supports of either a bolt in style or an adjustable concreted anchor.

Bolt down post anchors

Bolt down post anchors


Concrete anchor for posts

Concrete anchor for posts


The frame is constructed as above but will be utilising joist hangers for added strength.

If the deck is over 60cm in height we strongly recommend a rail to prevent a nasty fall.

Also, any cut timber or drill holes would benefit from a timber treatment

I hope this has been helpful.  If you need any help or advice with your decking project please contact us