ABOUT LOFT-E®

OUR JOURNEY FROM DESIGN TO INSTALLATION

The LOFT-E® adjustable loft leg was invented by UK Loft Boarding Ltd in 2018, it evolved from the concept that loft boarding is required to be raised above the insulation so that when the floor sub-frame is fitted it allows the continuation of airflow around the loft. Boarding directly down onto the joists or compressing the insulation is now considered to be the absolute incorrect method of loft boarding.

We noticed plenty of other products on the market, while they work. We knew that we could design a more sustainable, robust, adjustable loft leg that could stand out from the rest. The vast majority of loft legs on the market are more aimed towards the DIY market; LOFT-E® is specifically supplied to approved installers to ensure that only the best of the best are installing the product.

When choosing the material, it was a no-brainer for us to go with 100% recyclable steel over the ever-popular choice in this market, plastic. A problem that plastic products face in a loft are the consistent temperature changes, plastic softens during the heat of summer and therefore has the potential for the legs to buckle and the storage floor to collapse. This can also happen in the cold of winter with the legs getting so cold that they can become very brittle and can have a tendency to fracture, again leaving you with the same problem.

Heat changing in your loft as well as other factors can also cause your ceiling joists to warp and twist over time, leaving your joists uneven, which is a really common issue that we come across with new builds varying from brand new to 20 years old. When installing a raised loft floor sub-frame, the floor needs to be level therefore static loft legs require having to resort to packing pieces and wedges which we don’t consider to be a sufficient way to support a loft floor. That’s where our LOFT-E® ADJUSTABLE loft leg comes into play, not only can it raise the sub-framed floor above the insulation to 270mm or more, it can also be adjusted to compensate for the variations in joist height. A fantastic solution to a simple problem.


Testing at Lancaster University

Many installations later with absolutely no issues we then approached Lancaster University engineering department to see if they would like test our products for all aspects of strength and thermal measurements to really find out how good our loft leg was when it was pushed to its limits.

We were invited to visit Lancaster University’s engineering facilities to have a look round and discuss the project. They have various facilities to test numerous different aspects of a product. We had a great day looking at all the equipment and facilities they had and would like to thank Professor Jianqiao Ye for their time to show us around and discuss our LOFT-E® product.

We know our product is very capable of doing its job, but we wanted genuine proof that LOFT-E® stands above the rest when it comes to strength, adjustability & thermal testing. We made arrangements with Lancaster University to test our product for strength, buckling, twisting, downwards & sidewards force, heat & cold effectiveness, thermal bridging and many more tests that can be found in the 80+ page report that they produced. All of the results were extremely higher than anticipated. In fact, our storage is stronger than your roof and ceiling structure per m².

They put a team together consisting of Cole Chesterton, Naeem Khan, Harrison Beaumont, Mackenzie Clark & Greg Wray and we sent some LOFT-E® samples to the University for them to test and evaluate. Over a period of weeks, we had online team meetings to discuss certain aspects and progress of the testing. In the final meeting, everyone involved was on camera going through all of the testing that had been completed.

Now that we have given you an insight as to where LOFT-E® came from, why don't we delve into the facts and figures of just how effectively LOFT-E® performed?


Maximum Stress from a single leg

The sheer stress that a single LOFT-E® leg can withstand is simply outstanding. Lancaster University tested all different points of our product regarding stress in all of the different areas of the leg as well as the stress across an array of legs. Did you know that one single LOFT-E® leg can withstand 4.8 Tonnes of compression force?!

Having applied a varying load from 0-10000N, the maximum stress experienced by the body was plotted for each loading case in the below.

Maximum stress experienced by the whole structure when loaded from 0-10000N (structural steel) The above shows a linear increase in the stress experienced by the body which was to be expected as it is proportional to the applied load. Plotted on the same figure is the factor of safety for each loading case, for instance when 500N is applied, the factor of safety is approximately 5. As a result, the maximum stress experienced by the body is equal to 5 times the yield stress of the material. This value rapidly decreases and falls below 1 after 2500N is applied, showing that the structure has yielded and will then plastically (permanently) deform.


Maximum Stress from an Array of legs

When we combine numerous legs together the weight that out LOFT-E® system can take is way more than capable of withstanding your items to store in your loft as well as your own weight.

After carrying out yield strength analysis on the support it was possible to determine the exact point at which the component will fail. From this, the maximum loading capabilities could be determined for both a singular leg and an array.

From the data displayed in Figure 15 the maximum allowable load was determined from the equation of the line as in equation 1 below. The linear trend was found to have an equation of:

𝑦 = 0.1009𝑥 − 0.0027

Where y represents the stress experienced by the body and x represents the force applied. Knowing that the yield stress of the material was 250MPa, the equation was solved to find the load at which the support would fail.

250 = 0.1009𝑥 − 0.0027,
𝑥 = 2477.7𝑁

Therefore, the maximum load that a single leg can withstand before yielding is 2477.7N or 252.6kg. Using the data provided by UK Loft Boarding for the number of legs required for a given loft area (Boarding, 2020), the maximum loading was scaled from 6 to 192 legs.

The maximum loading value above does not incorporate a safety factor and therefore is the absolute maximum the material can withstand. Due to external factors that may weaken the support over time such as thermal expansion or corrosion, a safety factor of 2 was added to the model to ensure the supports remain safe over time and represents conditions within a loft space (a safety factor of 5 is under extreme conditions that would never be encountered in a loft space). This factor of safety is adjustable at the discretion of the company to accommodate their needs, Figure 22 and Figure 23 show the maximum allowed load and equivalent mass, with and without a safety factor.

Figure 22: Maximum allowable load for an array of legs

Figure 23: Maximum allowable mass for an array of legs

 

Even with a safety factor of 2, a single leg is still capable of carrying 126.3kg which is a significant load. Scaling this up to the smallest loft area of 4x4 feet requiring 6 ‘LOFT-E’s it was found that the maximum mass the array can hold is 757.7kg. This value seems more than adequate for the needs of the company and shows the design of the product is fit for purpose.


Thermal Aspects

The LOFT-E® Adjustable Leg went through thorough testing regarding thermal aspects. These included the heat transfer between the ceiling joists and the sub-frame. We wanted these tests to prove that even though our product is made out of 100% recyclable steel, there is no problem with heat transfer therefore any affect concerning condensation.

The simulation was organised such that it was representative of the physical conditions that the loft leg would operate in. As depicted prior in the block diagram, Figure 47, there will be a temperature differential between the room below and the loft space, with heat being transferred through the ceiling to the loft via the layers and the component layers. Thus, the ANSYS steady state thermal simulation was set such that these conditions were represented.

Thermal conditions were set such that the bottom face of the model, the room ceiling, and the top face of the model, the loft floor, had different temperatures. The room below was assumed to be standard room temperature of 22°C and the loft to be a value of 2°C, this temperature differential was to set an initial benchmark for the first results of the simulation. Later goals of this model were to provide the temperature variation across the component for a range of temperature differentials, such to be representative of regular seasonal temperature fluctuations but also irregular extremities. The model thermal configuration is depicted in Figure 50.

Figure 50: Thermal model conditions configuration

The labelled sections A through C in Figure 50 detail the application of temperatures in the model. The applications are as follows:
• Position A, representing the ceiling of the room below, utilises a temperature application of 22°C.
• Position B, representing the loft floor, utilises a temperature application of 2°C
• Position C, is a face application to the ceiling layer with a benchmark heat flow of 5W
Next, the appropriate material properties must be applied to each respective component layer of the model, such that the actual thermal conductivity of the component is representative of the actual product.

Thus, utilising the data provided by ANSYS as well as manual input of thermal conductivity values provided by the company, the inputted material properties and respective assignments are detailed in Table 7.

Table 7: Material assignment and properties

SIMULATION RESULTS

Figure 51: Thermal model temperature results (with insulation layer)

Figure 52: Thermal model temperature results (hidden insulation layer)

Figure 53: Direction of total heat flux through component

 

The initial results obtained from the fully meshed model are detailed in Figure 51 through Figure 53. The temperature varied as expected, with a sharper increase in temperature drop across the foundational timber truss member and bottom saddle of the component. The component demonstrated a steady decline in temperature with distance from the bottom surface, reaching equilibrium with the loft space temperature at the top surface of the model. In contrast, the insulative material fulfilled its purpose and demonstrated a lesser magnitude in temperature gradient from the bottom surface to the top. The heat flux vectors depicted in Figure 53 demonstrate that the component geometry creates concentrations of heat flow from the bottom saddle, which reach a significant magnitude at the boundary between the bottom saddle and the rod. The rod then acts as the most significant conduit for heat flow from the bottom surface to the top. Further, it can be demonstrated by the resulting thermal error in the model, depicted in Figure 54, that the results can be considered accurate. The maximum error region of the model occurs in a region of little priority, therefore, can be ignored.


Complete document

All the figures above show why our LOFT-E® system is far superior to any other product on the market. What we have shown on this page is only a small section of information, if you’d like to delve further into the data provided by Lancaster University, if you click the image below it will allow you to download the 80+ page document detailing everything you need to know about our LOFT-E® leg.

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