Showroom Open 10am-2pm Tues-Sat or call to book an appointment outside of these times

High Quality Composite Products Direct To Your Door – Buy Online!

Composite Decking Installation Guide

Composite decking is a great way to improve the look of your home and add value to your property. Not only is it a beautiful addition, but it’s also low-maintenance and long-lasting. This guide will show you how to install composite decking boards correctly so that you can enjoy your new deck for years to come.


1) Preparation Of Work Area

Clean and tidy area – Before you begin the installation of your new composite decking you must make sure your work area is clean and tidy and safe. If you are working on an existing decking sub-frame, make sure that the area is free of debris and that any nails or screws are removed. If you are starting from scratch, you will need to clear the area of grass, weeds, roots and other rubbish, leaving your workspace tidy.

Weed barrier – Once tidy, it is a good idea to put down a high-quality weed barrier, this will help to prevent any new weed growth underneath your new deck.

Level ground where possible – If you are starting from scratch it is important to make sure the ground is level, this will help make the installation process easier. Although the levelling of the decking boards is mainly down whilst building the subframe.

2) Storage of composite decking boards (until installation)

Store out of direct sunlight – To keep your new composite decking boards in tip top condition it is important to store them out of direct sunlight to help avoid potential warping (once the boards are securely fixed down this isn’t usually a problem).

Protected from weather – Although even the harshest weather conditions wont damage your boards we would recommend keeping them out of the weather and covered up prior to installation. This will make the process of fitting your boards easier.

Laid flat, off the ground supported at 500mm intervals – Composite decking boards should be stacked on top of each other off the ground using supporting wooden batons at regular 500ml intervals. This will help to avoid the boards from bowing over time.

3) Handling of decking boards

Lifted and placed rather than dropped – When handling decking boards, to prevent damage or scrapes and scuffing they should always be carefully lifted and placed down gently whilst moving/relocating them before installation.
No sliding boards against each other – Another way composite decking boards can become damaged is by sliding the boards along each other whilst picking them up, this can mark the boards so always avoid doing this where possible.
Carried in the middle on the edges for best support – When moving, decking boards should be carried in the centre and on their edges for optimal support.
During installation avoid sliding equipment across surfaces – Try to avoid sliding the decking boards across all surfaces (not just other boards) when installing them, this will minimise the risk of the decorating face of the boards from being scuffed or scratched.
Surfaces kept clear of construction debris – Make sure all construction debris is regularly swept up and disposed of, cleaning up as you go. This will reduce the chances that your decking boards will be damaged. It also makes cleaning up at the end of the job much easier, bonus!

4) Safety Equipment & PPE

Safety goggles/glasses – A good pair of safety goggles or glasses should be worn at all times when working with any tools or equipment.

Dust mask – A dust mask should always be worn when working with any kind of power tool as it will help to avoid inhaling any harmful dust particles that may be created during the work.
Hearing protection – It is always a good idea to wear some form of hearing protection, ear plugs or ear defenders when working with any kind of power tool to avoid any long-term damage to your hearing.
Work gloves – Gloves are always a good idea when working with any kind of construction project as they will protect your hands from cuts, scrapes and scratches as well as splinters.
Long sleeves & trousers – To avoid any skin exposure it is always best to wear long-sleeved shirts and trousers whilst working on any construction project, this will also help to protect you from the sun if you are working outdoors.

5) Tools & Equipment

Circular Saw – To get the cleanest cuts, we recommend a 60T+ Aluminium/laminate multipurpose blade.
Mitre Saw – Extremely useful for getting accurate cuts on long lengths of decking boards.
Jig Saw – Very useful for cutting around obstacles such as posts, make sure you use a fine downward cutting blade if cutting through the decorative surface of the composite boards to prevent damage.
Power Drill / Driver – A small drill bit should be used for drilling pilot holes in your decking boards were required to prevent the composite from potentially splitting where screws are used. Screws can be screwed into the decking structure using your power drill/driver, there is also a torque feature on most drills to prevent over-tightening.
Countersink drill bits – Useful for ensuring screws are flat to all surfaces, this will help to avoid any raised screw heads which could potentially become a trip hazard.
Tape Measure – Probably one of the most important tools, you cannot accurately measure lengths without one, measure twice and cut once!
Set Square – To mark out and cut your decking boards accurately a set square will be required, otherwise, you may end up with wonky-looking decking.
Pencil / Marker Pen – To mark out the lengths of your decking boards before cutting them a pencil or marker pen will be required.
Spirit Level – A small and large spirit level will be required to check that your decking frame is level as well as to check the individual decking boards once installed, this will help to ensure an even and level surface.
Clamps – Used to secure the decking boards to the subframe, allowing for slight adjustment before fixing them into the composite decking clips. These T-Clips are perfect for composite decking installation, once you are happy that your boards are in the correct place, tighten/screw the clips into position and remove the clamps.
Stringline – A string line can be used to help you keep your decking boards in a perfectly straight line as you fit them, this will help to avoid any wavy-looking decking.

6) Calculating amount of boards needed

Measure length and width of the proposed area – To work out how many decking boards you need you should start by accurately measuring the length and width of the area. To work out the square metres you would then multiply the length by the width.

For example, a decking area of 5m X 5m would equate to a 25 SqM area.

How many Decking boards do you need? – As composite decking boards should be laid using full lengths and not using offcuts 2 boards would be required per 1SqM metre, so for the example above, for a decking area of 25sqM, 50 composite boards would be required to the top surface area, additional boards will be required for the fascia boards depending on the height off the ground.

Allow 5% for wastage – Now you have determined the number of composite decking boards you should add 5% to the total to allow for wastage during the installation process.

7) Decking fixings & accessories

Starter clips – To begin laying composite decking boards you will need Starter Clips, these will be used to attach the outer edge of the first decking board to your subframe.
T-Clips – Once you have laid and secured your starter clip in position, you can then add additional boards using T-Clips which will secure the remaining decking boards in place.
Angle Edge Trim – A decorative edge to your decking, these edge trims are used to finish off the decking once all deck boards have been installed.
Bull-Nosed Boards – These are perfect to create composite steps if your decking design requires them, they can also be used to finish off the decking rather than using angle edging trims.
Screws – Although not required when using the starter clips and t-clip system to fix your decking boards, there are occasions where screws may be required, you must use screws specifically designed for composite decking.

8) Falls & Gradients

It is recommended that composite decking boards be installed at a 1% gradient. This will help water run off the decking, water will run off parallel to the direction of fall, through the pre-formed grooves in the boards, and so lowering the danger of slipping when wet.

Sub Structure (If you are building one)

9) Installation Of Sub Structure

Setting out corners – Start by measuring and marking out the corners of your decking area using pegs, string and a spray can or line marker.
Fixing plate against walls – To attach the subframe to any existing building or structure you should use a wall plate which should be fixed flat against the existing wall.
Posts & joist spacings – Depending on design needs, decking can be fastened to pressure-treated softwood joists (C16 – EN14081 or similar) or composite/aluminium joists. Stainless steel or galvanised countersunk wood/masonry screws should be used to fasten all joists at 400mm intervals. All joists must be secured in at least three places to ensure the decking subframe is sturdy.
String line – To ensure your decking subframe is square and straight it is a good idea to use your string line, to help mark out the area for your joists.
Joist Direction – When planning your decking you should try to make sure that your joists run perpendicular to your composite decking boards.
Installing Bearers – Bearers are the frame that your joists will sit on and are generally positioned at right angles to your joists, they should be fixed into place using coach screws or similar.
Recommended 1% drop – To allow water to drain off the surface of your finished decking we would recommend a slight drop to allow water to run off away from any buildings.

Decking Board Installation

10) Orientation of decking boards

The orientation of the decking boards should be perpendicular to the sub-frame direction, however, depending on your design, there may be times when this isn’t possible.

11) Cutting boards (if required)

Use the correct blade – When cutting composite decking boards you must use the correct blade for the job. The ideal blade is a fine tooth, downward cutting blade for hand saws, and with a circular saw, use a 60T+ Aluminium/laminate multipurpose blade. These blades are ideal for cutting composite decking boards.
Measure twice, cut once – It is better to make sure your measure your cuts twice before proceeding to cut your materials, double checking can save on wastage.
Cut to length to rest on joists correctly – When cutting boards ensure that they are cut to rest on the centre of joists, this will make sure there is enough support for the ends of the boards when being walked on.

12) Starter clip installation

Positioning Of Starter Clips – Starter clips should be placed on the front edge of your decking subframe, positioned on the centre line of each joist, and flush to the end of the joists.
Pre Drilling holes – To avoid the possibility of splitting the joists and to ensure the clips are secure, screw heads flush it is recommended that you predrill the holes for the starter clips using a small drill bit.
String line – Once you have your first Starter clip in place, you can use a string line to line up the remaining starter clips on the remaining joists.

13) Install the first decking board

Fully engaged with the starter clips – Now that your starter clips are in place you can proceed to install your first decking board, tuck the front edge into the starter clips and push firmly in place until the decking board is in the correct position and fully engaged with the starter clips. Ensure that the first board is square correct as all the other boards will follow suit.
T-Clips – T-Clips should be used on the opposite edge of the board, on the joists directly opposite and inline with your starter clips, ready for the second run of boards. These should be loosely screwed in place, this is to allow for slight adjustment with boards whilst placing them.

14) Installing the second fun od boards

Offer the board up to the T-Clip – Gently offer the composite decking boards up against the T-Clips, making sure that they are engaged and secure. Do this along the entire length of the boards, making adjustments if necessary.

15) Fully secure T-Clips

Tighten T-Clips – Once the second run of boards has been placed and you are happy that they are engaged with the T-Clips, and in the correct position, you can then go ahead and tighten the screws on your T-Clips.

16) Installing Subsequent Boards

Repeat the process – We have now outlined the process of placing your subsequent runs of composite decking boards, follow the steps above for all remaining boards until your decking area is covered.

Finishing Off

17) Fascia Boards

Adding facia boards to the subframe encloses the decking and is the final step of the process of installing boards. These fascia boards are usually identical to the composite decking boards, starting from the top edge of your decking and working down. Depending on the finished height of your decking you may need to add multiple runs of these fascia boards. T-Clips should also be used to seamlessly fix these to your subframe uprights.

The last run of fascia boards may require some adjustments along their bottom edge, cutting lengthways along the boards, the angle of these cuts depends on how level the ground is.

18) Edging Trim

Now that you have installed your fascia boards and decking boards it is recommended that you use an angled edging trim to finish the decking giving it a professional look and feel. Edging trim should be used where the fascia boards and decking boards meet along the top edge of the decking structure and any vertical corners.

Cleaning & After Care

19) Pressure cleaning

Fan-shaped nozzle – When pressure cleaning your composite decking boards you should always make sure the nozzle of your pressure washer is set to fan-shaped, this will get better coverage and also avoid damaging the surface of the decking boards.

Use low pressure – reducing the pressure of your power washer is advisable if possible, this helps to avoid damaging the surface of the composite decking boards. If your pressure washing doesn’t have a pressure adjustment simply hold the nozzle slightly further away from the surface of your deck boards.

Pressure washing is great for removing surface debris, but other methods should be used as well.

20) Soft brush

Warm soapy water – Using a soft brush and soapy water, gently scrub the surface of your composite decking boards, rinse and repeat until you are happy that your decking is clean.

Specialist cleaning fluids – Specialist cleaning fluids are available to buy online.


Now that you know how to install composite decking boards, the process should be a lot easier. We have outlined the entire installation process for you, from start to finish, so you can follow along easily. If you have any questions or run into any problems during the installation process, feel free to reach out to us and we will help you as best we can.

Alternatively, if you are located near our showroom in Derby we also offer a composite decking installation service if you don’t feel confident with installing your own decking.

Thanks for reading!

Share This Article...


Read More of Our Articles...

Do you require installation services?

We understand that not everyone is comfortable with DIY so if you would prefer to hire an experienced installer please fill out the form below and we will be in touch if we think we can be of service.

Contact Information
Which products are you interested in?
How soon would you want installation?