Decking

Decking has became very popular over the years as a garden surface, and justifiably so. It can be used for many different activities, it is quick and easy to lay and most importantly it also looks good too.

This is a very quick guide to the basics of building a deck.

In essence there are two types of decking, raised decking and ground level decking. Ground level decking is decking which is built upon a flat, supportive, level surface, classic example being decking which is built upon an old concrete patio. Raised decking is built over bare earth or unlevel ground and raised off the ground, it may be raised a few inches or several feet. Deciding which type of decking you are building is first choice as it dictates what material you will need. At growgarden.co.uk we supply the required material for both types.

Decking consists of three elements…

Decking boards.

These are what you see when you walk on decking, they are designed to be decorative, robust and long lasting. They don’t however provide the strength of the decking, this is provided by the…

Framework

The supporting framework of the decking is the most important element, it provides the strength and level surface for the decking boards to fixed to. The framework consists of beams and joists which are screwed or nailed together. Raised decking must use strong joists in order to prevent flex and bounce in the decking.

framework for small decking being constructed

Posts

The final element of decking is the supporting posts, these are only used in raised decking and ensure that the framework is level securely fixed to the ground.

Now that we know what lies behind the decking structure, we move on.

Measuring up.

In order to work out the amount of material you require, you first need to measure the width and length of the area to be decked. If the area is an unusual shape you can do this in sections.

You can then plan your supporting framework, best to do this a getting a piece of paper and creating a rough drawing of the decking. Think about what way you want the final decking boards to run and remember that the joists must run at 90 degreses to these. The framework consists of a perimeter of timber all around the decking area(header joists), plus joists traversing the perimeter, perpendicular to the direction in which you wish the decking boards to be laid. Your joists should be spaced at 400mm intervals for raised decking and 600mm for ground level decking. Again you can work this out in sections if the decking area is an awkward size.

You can then work out how much timber you need all timber for the supporting framework comes in either 3 meter or 3.6 meter lengths. Remember you don’t want any joins in your joists unless your decking is wider than 3.6 meters. So if your decking is 2.5 meters wide and your need twenty joists to cover the length, then you will need to order twenty lengths of joists and loose half a meter in each length.

You use the same principle to measure how many decking boards you need as well. Again remember that you don’t want any joins unless the deck is wider or longer than the length of the decking boards. Decking boards come in 3.6 meter, 4.2 meter or 4.8 meter lengths. Also remember that your decking boards must run at 90 degrees to your joists.

Building the Decking

Before you start building and fixing your framework, take time to clear the ground of any plants or grass, then cover the ground with a weed suppressing membrane and cover with some plain gravel. There is nothing worse than weeds appearing through your brand new decking!

The most difficult part of any decking is getting a good framework constructed. Don’t skimp and take your time on it. Make sure it is level with a slight run off for the rain, in the same direction is the top decking boards. A well constructed framework will ensure that your decking is solid, long lasting and looks good.

Ground level decking.

For ground level decking you will need the joists and perimeter wood to be 100mm x 50mm (4”x2”), or 125mm x 50mm (5”x2”). You can simply screw the joist together, as they will be supported by the ground underneath. For any small differences in the ground height you can use small concrete slabs to support the decking.

Raised Decking

For raised decking you must use 150mm x 50mm (6”x2”) joists, don’t be tempted to use thinner joists as they will not be strong enough and the resultant decking will move underfoot. In this type of decking it is also best to use joist hangers instead of screws to support the joists to the header joists.

You will also need to purchase posts in order to raise the framework of the ground. These posts will need to be 100mm x 100mm (4”x4”) and bolted to the joists. They will need to be bolted to the outside joists at no more than 2000mm (6’) intervals. If the decking is wider than 2 meters it is also worth putting a post in the centre of the joist corresponding with the header joist (see above). Make sure your posts are concreted into the ground.

If your decking is to be connected to the house you can bolt a joist directly to the wall of the house and use this as part of the framework, ensure that the decking lies below the damp membrane of the wall otherwise you might experience damp issues laters. You can usually tell the location of the damp membrane by a thicker than normal layer or mortar between the bricks.

Finally the decking boards, this is the easy bit. Secure these to your framework at 90 degrees to the joist direction, screw or nail them to the joist using two screws in each board on every joist. Then simply cut off any protruding pieces of decking board and hey-presto a completed deck!

You can screw a decking boards around the outside of the decking to hide the header joist and even at trellis at the bottom if the decking is particularly high.

(Please note that note this is a basic guide and you construct any decking or other projects at your own risk. Growgarden.co.uk will not be held liable for any damages or loss to persons or property caused by following this or any other guide on this website.)