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If you have more questions please contact us and we will be happy to help you.

What about fire? [Back to top]

ModCell® Straw bales are tightly packed and covered with lime render. Fire needs a ready supply of oxygen to burn and, without it, no combustion will occur. The panels provide a near airless environment, so fire resistance is very good. Lime rendered ModCell® Traditional panel has a 2 hours and 15 minute fire certificate, over double the current UK Building Regulations requirement.

What about infestation? [Back to top]
Straw contains very little nutritional value and will not, in itself, support a pest population. The density of straw discourages rodent activity. Infestation can only occur when panel has been damaged and straw is open to external atmosphere. ModCell® Hemp is a monolithic structure not dissimilar to lightweight aerated concrete and as such prevents infestation occurring. Lime render is aseptic further reducing the possibility of infestation.

Will the straw decompose? [Back to top]
ModCell® panels are designed to be breathable and prevent the buildup of humidity levels. It is high humidity levels that causes decomposition to take place. Straw begins to decompose when the moisture content exceeds 25%. Our researc has shownthat the moisture content of ModCell® is less than 15%, well below the level at which decomposition becomes a potential risk.

What about damp? [Back to top]
ModCell® is delivered to site as closed panels with all but the finishing surfaces applied. Relative Humidity (RH) and moisture levels are measured at the factory gate. Research has shown that damp is kept at bay naturally as part of the breathable properties of the materials used

What about mould? [Back to top]
Lime is highly alkaline. The pH, moisture content and air changes from the panels 'breathing' prevent fungal and microbial activity.

What sizes do they come in? [Back to top]
A variety of sizes can be supplied. Please contact us for details.

How thick are the panels? [Back to top]
ModCell® Traditional panels are 480mm deep.

ModCell® Core at 400mm deep plus battens and cladding on both the internal and external face.

ModCell®  Core + 440mm plus internal battens.

Why are they so thick? [Back to top]
To accommodate standard size UK straw bales. To meet the same u-Value using brick block and mineral wool, insulation the wall would need to be 533mm thick.

Does ModCell® help towards the thermal mass of the building? [Back to top]
ModCell® has an optimum combination of mass and super insulation. ModCell® Hemp has higher thermal mass than ModCell® Straw. Both products deliver a thermal lag of 8 hours, which is optimal for most uses.

What are the u-Values? [Back to top]
This is dependent on the panel type:
ModCell® Tradtional     = 0.19
ModCell® Core             = 0.13
ModCell® Core +          = 0.11
Insulation values are nearly 3 times higher than current regulations require.

ModCell® solid timber frame = 0.134
Insulation values are nearly 3 times higher than current regulations require.
ModCell® panels deliver an airtight construction, to PassivHaus specifications. As a result, buildings using ModCell® can help deliver zero heat requirements, saving money and CO2 emissions. BaleHaus® has an air tightness of 1m2/(h.m2) at 50Pa , 10 times better than current regulations require.

What about Carbon? [Back to top]
ModCell® panels are 'carbon negative'. Embodied carbon - A 3 x 3.2m ModCell® panel has equivalent of 1400kg of atmospheric CO2 locked up in its fabric. A typical two story BaleHaus® of 100m2 banks almost 43 tonnes of atmospheric CO2

How are they made? [Back to top]
The structural timber frame is ‘infilled’ with straw bales, which are stacked to form a wall, compressed and held together for stability. The wall is then either rendered using a protective breathable render, or clad with timber or other cladding materials

What are they made of? [Back to top]
Straw bale, timber, lime render, breathable renders or wood cladding and small quantities of steel fixings. They are precision-engineered using modern methods of construction (MMC).

How heavy are they? [Back to top]
Weight varies by type and panel size. A fully rendered 3m x 3.2m weighs approximately 1.6t

Are they sustainable? [Back to top]
Yes, ModCell® panels are made from almost 100% renewable materials. ModCell® Panel frames are constructed using certified legal and sustainable timber using the CPET standard and include FSC or PEFC certification as standard. All straw, which is an annual 3m tonne by-product of the agricultural industry, is untreated and locally sourced. At end of life the panels can be disassembled and all elements either re-used, recycled, used as biomass or safely composted.

Is there waste from the manufacturing process? [Back to top]
Straw bales are cut to size in the Flying Factory™ and trimmings and rejected material are composted, used as bedding for farm animals or recovered as biomass. The frame is made using offcuts from the timber industry. Cut materials from the frame manufacturing process are used in the factory’s biomass boiler. Cut waste is minimal as each panel is precision cut from larger sheets using CNC equipment. Lime render is spray applied with almost no residual waste. Offcuts of stainless steel and are minimised by the design but are collected and recycled via the scrap industry.

Do they cut noise levels? [Back to top]
Yes they produce an approximate reduction of 50db

Are there different finishes available? [Back to top]
Yes, natural coloured lime render, lime wassh colour finishes, breathable rendres, as used on ModCell® Core +, is available in a range of shades. Clienrs who want alternative finishes should contact us to discuss their requirements.

How do you incorporate essential services like plumbing and electricity? [Back to top]
Electrical conduit can be installed behind the lime render face in the flying factory. Alternatively ModCell® Core and ModCell® Core + allows for services to be installed in the void created by the battens between the internal face of the panels and the internal finish layer/plaster board.

Are they load bearing/structural
? [Back to top]
Yes, with some considerations. On commercial buildings ModCell® is normally secured to a building frame. ModCell® can be used for structural load bearing and stabilisation. Normally Modcell® panels are structural up to 3 stories high. Above this height we would advise the use of ModCell® panels as a panelling system fixed to a frame.

How high can you build with them? [Back to top]
There is no limit to the height of buildings in which ModCell® can be used. Although they can be structural in their own right up to three stories high.

Can I build with a frame? [Back to top]

Yes, Modcell® can be used with timber, steel and concrete frames.

Do you build them onsite? [Back to top]

No, ModCell® is an offsite prefabricated panel system - (see below)

Where are they made? [Back to top]

ModCell® panels are either fabricate in a central manufacturing unit or within a local ‘Flying Factory™’. If ‘Flying Factory™ option is chosen we work with local farmers to identify a source of straw and a suitable location to assemble ModCell® panels, normally within 3 - 15 miles of the construction site. By using local skills labour and materials, we keep more of the project’s value within the local economy and reduce CO2 emissions.

What quality controls do you have? [Back to top]
ModCell® panels are entirely manufactured and assembled under controlled conditions. The quality of each panel is assured and signed off at various stages during manufacture. ModCell® is delivered to site as fully closed panels. Moisture content levels are constantly monitored throughout the manufacturing and delivery process.

What is the lead time? [Back to top]
12 - 16 weeks from confirmed order.

How long do they take to install?
ModCell® is delivered to site in nominal 3 m x 3.2 m panels.  A typical 3 bedroom house can be erected and made watertight in 3.5 days. Final finish coat of render, if required, is done at a later date.

What equipment is needed to install them? [Back to top]
On construction site – Crane or telescopic lifting device. Scaffolding or cherry picker.

Can I buy them in kit form? [Back to top]
No. Currently manufacturing quality controls prevent the manufacture outside of factory environments. Although we are happy to engage with community groups and individuals who want to assemble panels. This would be after appropriate training and supervision.

Do you supply to self builders? [Back to top]
This is dependent on the size of the development and will be reviewed on a case by case basis. Additional traveling distances from 'Flying Factory™' may have an effect on cost per unit and an increase in CO2 emissions.

Can you help me with my design? [Back to top]
Yes ModCell® are able to offer a number of service options to the developer. These include:
Supply only

Supply & fit

Design & supply

Design, supply & fit

Full turnkey solution

Consultancy and CPD training.

How long do they last? [Back to top]
Life cycle would be the same as a traditionally constructed building. At end of life they can be easily reused or disassembled. Straw and wood are biodegradable and can be used as biomass. All metal fixings can be recovered and recycled. There are a thousands of straw bale buildings throughout the world, some of which are over 120 years old.

How much do they cost? [Back to top]
Costs are dependent on panel type and panel design. Please call to discuss


Where can I get my building insured? [Back to top]
There are a number of insurance brokers who offer insurance, an example is M & DH Insurance Services Ltd (


Do you supply complete building packages? [Back to top]
es ModCell®are able to offer a number of different whole building solutions across market sectors. Please see the following brochures for more information:
ModCell®Renewable Schools;
ModCell® Renewable Retail;
BaleHaus® by ModCell®.

Supply only

Supply and fit

Supply design and fit

Where can I see one? [Back to top]
There are a number of sites around England and Wales. These include:

Nucleus Building Hayesfield School, Bath
Inspire Bradford Business Park, Bradford.
May Park Primary School, Bristol
Weydon School, Farnham, Surrey.
Straw Bale Café, Holme Lacy Hereford.
Waterfoot Primary School, Waterfoot.
Castle Park Primary School, Caldicott.
Think Low Carbon building, Barnsley.
LILAC CoHousing Project, Leeds.
Faculty of the Built Environment, UWE, Bristol.
Torfaen EcoBuilding, Cwmbran.
York EcoDepot, York.
Knowle West Media Centre, Knowle West, Bristol.