Millboard Decking FAQs
A collection of frequently asked questions about Millboard Composite Decking.
Millboard decking is extremely versatile and can be used in practically every outdoor space (subject to building control). Create decks, cladding, balconies, roof gardens, boardwalks, bridges, pontoons, seating, steps, planters and more. Millboard can be used as the decorative face for most outdoor designs, as long as it is fixed to a structural element.
The responsibility for the decking and cladding’s suitability in the required location is to be determined by a certified building professional (building control, building insurance, fire officer, etc). Millboard will not be held responsible for incorrect specification, application, or product installation in areas not in accordance with government guidance, in the UK or abroad. Current guidance should be gained from the government website relating to the geographical project location.
When you take your first look at your new Millboard decking boards, you will be amazed at the attention to detail and quality before you. You’ll notice how lightweight yet durable the boards are, ready for immediate use.
There are a few things we advise users to be aware of before diving in and building that dream project:
+ A release agent will be present on the surface of the boards when you take delivery of them, which may give a slightly shiny effect. This release agent has been applied so that the finished board can easily be removed from our moulds and will disperse in the weeks following installation.
+ Like wood, no two Millboard decking boards are the same colour, with the subtle differences giving the most natural appearance. This is to give your decking all the good looks of a wooden deck, but all the structural benefits of a composite deck.
+ Our boards are moulded under extreme pressure and not extruded, so some dimensional variance is expected. The tolerances that we permit for the size of our decking boards are limited to: Width: ± 3mm. Length: ± 5mm. Thickness: ± 2mm.
+ As with wood, it may be necessary to trim the ends of the boards during installation, in order to achieve a flush, clean finish.
Following extensive trials, we recommend and supply Durafix® stainless steel screws, designed specifically for Millboard – this is a requirement of our limited warranty. There’s no need to pre-drill or countersink Millboard decking, and the unique Lastane® material coating flexes back over the screw-heads, leaving a minimal witness mark. This may be more visible on the lighter colours. Should some of the screws leave larger witness marks, these can be filled. Our installation guide should be followed at all times to achieve the best possible results.
Millboard has been designed to replicate the natural variances of wood and we do not intend for the product to have identical shades. Buying all the Millboard decking you need at the same time should help to ensure that the colour is as consistent as possible and we would always recommend laying out the boards before installation, to create an effective, subtle blend.
Samples are provided as a representation of the product and we would encourage customers to view full boards as part of a deck, in order to fully appreciate the product, prior to purchase.
We go to extraordinary lengths to recreate the look of natural wood. As with all products exposed to the elements including sunlight, snow and rain, Millboard will naturally weather and tone down over time. Slight yellowing, especially in the deeper grain of our decking boards will be visible and loss of gloss is also expected and intentional. This is in order for us to replicate that natural piece of wood it has so carefully been moulded against along with our unique hand coloured process.
As with all composite products, the surfaces of the boards tend to be hotter than wood when exposed to direct sunlight. Darker colours particularly will feel hotter and may be uncomfortable to walk on in bare feet. Under direct sunlight and high temperature, footwear may be necessary. Special caution should be taken when using decking in areas by heat/UV reflective glass, or around pools.
As Millboard is made from a resin mineral composition it is stable in comparison to wood or composites based on wood, the amount of movement that is acceptable is up to 0.2%. We recommend a 4mm gap between the sides of boards and a 1mm gap between the ends of boards, a 10mm gap should be left between the boards and any solid surface to aid drainage.
As the boards are a moulded product we use a release agent in the manufacturing process so when the boards are first delivered this release agent is still on the surface. This may result in the boards looking like they have a shiny or waxed surface or have small particles of dirt and water puddling. This release agent will come off the surface within 6-8 weeks due to natural weathering. This process can be accelerated by cleaning the boards with warm soapy water and stiff brush after installation.
Please be aware that while the release agent comes off, the boards may be more slippery underfoot. In commercial settings it should be considered that it may be required to accelerate this process by cleaning the boards with warm soapy water and stiff brush after installation.
When the boards are first laid they still have a release agent on the surface, this will come off within 6-8 weeks due to natural weathering and usage.
Surface water will always be more prevalent on Millboard due to it being made from a non-porous composition. Laying the boards to a slight fall away from a building will help to drain the water off the surface, however it will not drain all of the water off the boards. Adhere to relevant gapping on the sides and ends of the boards as per the installation guidance to assist drainage, the boards have a cupping tolerance of 2mm. Surface water can be taken off the surface of the boards with a brush or large squeegee, frost or ice can be removed by spreading white salt across the board surface. When the boards are first laid they still have a release agent on the surface, this will come off within 6-8 weeks due to natural weathering and usage. The release agent means that the water will form beads or globules over the surface of the boards, once this release agent has come off the water will dissipate across the board surface.
There will always be a slight variance in the board’s dimensions due to the fact that we mould from natural oak, and due to the pressure of the moulding process. Despite this, we calibrate the boards to maintain as consistent a profile as possible. The manufacturing tolerances are: Width: ± 3mm. Length: ± 5mm. Thickness: ± 2mm. The dimensions of the Weathered Oak style may vary more between moulds due to the fact that they are moulded from timeworn oak with minimal changes to the dimensions. When working with the boards, packers may be required to create a flush finish between two boards.
Please be aware that while the release agent comes off, the boards may be more slippery underfoot. In commercial settings it should be considered that it may be required to accelerate this process by cleaning the boards with warm soapy water and stiff brush after installation.
The Lastane® finish is highly resistant to food and drink stains and scratches, and everyday wear and tear. Sharp objects such as unprotected table or chair legs, spiked shoes, animal claws or metal planter bases can leave marks if dragged across the surface, so take care when moving these items around. The risk of marking from strong dyes and stains such as berries and animal droppings will be reduced if removed as soon as possible, this also applies to cooking oils or fats that come into contact with the surface of the Lastane®.
Please ensure to cover and protect the boards from any surrounding building or landscaping works, painting, rendering or cementitious dust that could contaminate or mark the surface, especially if the boards have been recently installed. Millboard will not be held responsible for issues arising from the boards being affected by foreign substances as this does not represent a fault with the product. We are able to recommend cleaning solutions that may be used to address contamination concerns or in situations where our guidance has not been followed.
If the board surface becomes dirty during installation, this should be cleaned as soon as possible using warm soapy water (dishwashing liquid) and a brush. Clean your decking once to twice a year to remove leaves and general dirt particles.
Cover the boards from any surrounding building works or painting that could mark the surface of the boards. Stubborn marks may be removed with a range of different cleaners depending on the mark. Please contact us for more information on technical@millboard.co.uk.
Pressure washers can be used carefully on Millboard decking for cleaning and rinsing.
We would recommend following the below guidelines:
- A PSI no greater than 2,000 should be used, with a 40 to 60 degree spread fan tip
- The head should always be kept around 300mm away from the surface
- Please note that using pressure washers may increase the chance of screw holes becoming more visible
- Direct, prolonged and intense contact could damage the surface of the boards
Yes Millboard provide a UK-backed Residential 25 year Limited Warranty or a Commercial 10/12 year Limited Warranty on decking products, to provide customers with piece of mind.
Millboard composite decking comprises a polymer resin core bonded to a unique elastomer layer. The core includes strong decking materials, such as fibreglass, polymers and mineral stone, making it a robust option for everyday use. Read the full breakdown of what what Millboard is made of.
As outlined in our Millboard install guide, it’s crucial to use a durable, well-drained subframe, such as aluminium or reinforced plastic, ensuring a 400mm joist spacing (300mm for commercial use). For the best results, adequate ventilation and longevity, use a Millboard subframe. You can cut boards using a mitre, hand, or jigsaw, and we only recommend using Durafix screws. The screw head disappears into the elastomer layer, making decking fixing simple. When installing Millboard decking, allow 4mm spacing between boards and align the cut ends over joists. There are versatile options for edging and fascia boards, including flexible bullnose or square edging.
Millboard decking costs reflect the quality, premium appeal and performance of the material, and the price can vary depending on the decking style, width and colour chosen. Refer to our brochure for up-to-date retail prices.
Millboard decking, including composite decking boards and the Enhanced Grain Collection, is available across the UK through approved suppliers and major installers. You can buy Millboard composite decking boards from suppliers which stock a range of Millboard products, including decking, fascia boards and Durafix stainless steel screws for a professional finish.
Millboard decking boards should last a long time, so you shouldn’t need to remove them, but if you need to replace a deck board, reposition it or access the subframe, you may need to carefully lift your Millboard decking.
If you plan on refixing the boards, use special caution to avoid damaging the surface of the Lastane®. The elastomer layer is key to Millboard’s durability. To remove and refix a single board, gently pry it up without damaging the surface and remove the screws from the subframe. To refix, screw the board back into place positioning the screws in different places. It can be difficult to locate the Durafix stainless steel screws once they’re screwed in. If you’re re-installing a fresh deck, ensure the decking aligns with the intended lifespan of the frame. Watch how to refix a deck board.
Composite decking offers excellent slip resistance compared to traditional wooden decking, even in wet conditions. Unlike wood decking, which can become prone to moss, algae, and mildew, especially during the wetter months. Composite decking boards are non-porous, so they aren’t vulnerable to the same issues. Moreover, Lasta Grip decking features integrated grit strips for greater traction.
The pendulum test value (PTV) measures the safety of a decking surface; composite materials typically outperform wooden decking in maintaining friction. Millboard’s Enhanced Grain decking has low slip potential even in wet conditions. Regular cleaning and ensuring proper drainage can help prevent unnecessary hazards.
When the boards are first laid they still have a release agent on the surface, this will come off within 6-8 weeks due to natural weathering and usage. Please be aware that while the release agent comes off, the boards may be more slippery underfoot. In commercial settings it should be considered that it may be required to accelerate this process by cleaning the boards with warm soapy water and stiff brush after installation.
Millboard decking is renowned for its durability and longevity, outlasting traditional timber decking. Made from a composite material featuring a blend of natural minerals and polymer resin, it resists rot, splintering, mildew, and moisture damage. Customers can benefit from a 25-year structural warranty.
Painting composite decking boards is not typically recommended. Modern composite decking is designed to be low-maintenance and durable. Painting Millboard decking voids the benefits of its high-performance surface and covers the hand-finished woodgrain effect.
Millboard decking is designed with exceptional UV stability, ensuring it resists fading far better than traditional timber decking, PVC or other composite options, which naturally weathers or fades over time. Millboard composite decking features a Lastane® coating fused to a mineral stone core, showing minimal changes in colour tone, after years of sunlight exposure, high temperatures and wet conditions.
While slight variations can occur between different batches, this is part of the natural variation inherent in natural timber.
Yes, you can cut Millboard decking. It is best done using a mitre, hand, or chop saw, ensuring clean and precise cuts at the end of the board. Make sure to use the recommended PPE when cutting composite material.