Learn More
About Hempcrete
As A Material.
Hempcrete is in a class of materials referred to as 'bio-composite' materials. These are materials that contain a material of biological origin mixed with a material of a mineral nature. One traditional material of this kind was cob which was a mixture of clay rich earths and barley straw or other such material that acted as an aid to evenly distribute the clay particles in the mixing stages and as a means of reducing shrinkage cracks in the drying stages. There are many variations of this kind of material throughout history and around the world. Another material familiar to some would be horse hair mixed with lime to form a plaster.
Hemp is a modern take on such old school materials. Such materials if properly finished are extremely durable and may last many hundreds of years. Originally Hempcrete was developed in France as a means of bringing many of the old timber-frame buildings in Brittany and Normandy up to some kind of modern standards without compromising the integrity of the old oak timber-frames. Modern materials such as modern insulation materials or those containing Portland cement are not very vapour permeable. This means that the timber tends to sweat and moisture that penetrates the structure cannot escape.
The result is damage to the timber-frame structure and failure of the insulating materials. It was discovered that a mixture of natural cements and/or lime binders with the crushed stalk of the industrial hemp plant created a material that was both robust and breathable and was ideally suited to replacing the old wattle and daub panels between the timbers. But just as hemp was sympathetic to the old oak in the buildings of northern France it was soon discovered that it had similar properties in relation to the human inhabitants. It subsequently began to be used for the construction of modern buildings. There are three main methods of using hemp in buildings, it can be placed into formwork, sprayed,
or laid in the form of precast blocks in the same manner as block-work walls are constructed. Here at Freistaat we focus mostly on the 'cast in place' method where a form is first constructed and the Hempcrete material is gently tamped into place.
Although it has some structural strength - providing lateral strength and stability - hempcrete is slightly 'spongy' in compression and so to create a stable structure it is usually placed around a structural timber frame. This frame can be either traditional oak frame, or the standard 4 x 2 timbers used in many modern buildings. Here at Freistaat we like to use a combination of both to give the 'wow' factor of traditional Oak structure but with the flexibility and cost effectiveness of modern stud-work construction.
How We Build
With Hempcrete.
Hempcrete can often be used to great effect in a mix of old and new timber construction. A standard 4 x 2 frame acts as the principle structure for the walls and a few traditional oak timber-framed features are used. Typically oak trusses to take the rafters. Not only does this give you the wow factor of traditional oak framing, it is also cost effective. So less of the 'wow' factor when you see how much it costs! Freistaat Garden Rooms are more expensive than the average garden room but we still believe they are great value for money because they are not to put it bluntly - a glorified garden shed. Our buildings are proper structures built to last.
They are essentially an extension to your home but just not attached to it, and are priced accordingly. 'High-end' they may be but they are built on a bespoke basis and use only the best quality materials, and building practices are used in their construction. Hempcrete is generally finished on the outside by cladding it with a weatherproof material - typically some form of wooden cladding, or rendered with a lime based render. The roofs are generally finished in some form of wooden shingle, or metal corrugated sheeting with a decorative paint finish.
Flat roofs can be covered in Epdm, or other rubber roofing material with green roofs also an option. Internally we use clay plaster as standard with various options for finishing in coloured lime plasters. Ceilings are finished in plain lime plaster as standard. Floors are either lime-crete if solid, or timber flooring if built on floor joists. Other options are available such as earth/clay floors, or other more standard types of flooring.
Call Us: 07890 724634
Learn More
About Hempcrete
As A Material.
Hempcrete is in a class of materials referred to as 'bio-composite' materials. These are materials that contain a material of biological origin mixed with a material of a mineral nature. One traditional material of this kind was cob which was a mixture of clay rich earths and barley straw or other such material that acted as an aid to evenly distribute the clay particles in the mixing stages and as a means of reducing shrinkage cracks in the drying stages. There are many variations of this kind of material throughout history and around the world. Another material familiar to some would be horse hair mixed with lime to form a plaster.
Hemp is a modern take on such old school materials. Such materials if properly finished are extremely durable and may last many hundreds of years. Originally Hempcrete was developed in France as a means of bringing many of the old timber-frame buildings in Brittany and Normandy up to some kind of modern standards without compromising the integrity of the old oak timber-frames. Modern materials such as modern insulation materials or those containing Portland cement are not very vapour permeable. This means that the timber tends to sweat and moisture that penetrates the structure cannot escape.
The result is damage to the timber-frame structure and failure of the insulating materials. It was discovered that a mixture of natural cements and/or lime binders with the crushed stalk of the industrial hemp plant created a material that was both robust and breathable and was ideally suited to replacing the old wattle and daub panels between the timbers. But just as hemp was sympathetic to the old oak in the buildings of northern France it was soon discovered that it had similar properties in relation to the human inhabitants. It subsequently began to be used for the construction of modern buildings. There are three main methods of using hemp in buildings, it can be placed into formwork, sprayed,
or laid in the form of precast blocks in the same manner as block-work walls are constructed. Here at Freistaat we focus mostly on the 'cast in place' method where a form is first constructed and the Hempcrete material is gently tamped into place.
Although it has some structural strength - providing lateral strength and stability - hempcrete is slightly 'spongy' in compression and so to create a stable structure it is usually placed around a structural timber frame. This frame can be either traditional oak frame, or the standard 4 x 2 timbers used in many modern buildings. Here at Freistaat we like to use a combination of both to give the 'wow' factor of traditional Oak structure but with the flexibility and cost effectiveness of modern stud-work construction.
How We Build
With Hempcrete.
Hempcrete can often be used to great effect in a mix of old and new timber construction. A standard 4 x 2 frame acts as the principle structure for the walls and a few traditional oak timber-framed features are used. Typically oak trusses to take the rafters. Not only does this give you the wow factor of traditional oak framing, it is also cost effective. So less of the 'wow' factor when you see how much it costs! Freistaat Garden Rooms are more expensive than the average garden room but we still believe they are great value for money because they are not to put it bluntly - a glorified garden shed. Our buildings are proper structures built to last.
They are essentially an extension to your home but just not attached to it, and are priced accordingly. 'High-end' they may be but they are built on a bespoke basis and use only the best quality materials, and building practices are used in their construction. Hempcrete is generally finished on the outside by cladding it with a weatherproof material - typically some form of wooden cladding, or rendered with a lime based render. The roofs are generally finished in some form of wooden shingle, or metal corrugated sheeting with a decorative paint finish.
Flat roofs can be covered in Epdm, or other rubber roofing material with green roofs also an option. Internally we use clay plaster as standard with various options for finishing in coloured lime plasters. Ceilings are finished in plain lime plaster as standard. Floors are either lime-crete if solid, or timber flooring if built on floor joists. Other options are available such as earth/clay floors, or other more standard types of flooring.
How Is A Hempcrete Building
Different from A Normal Garden Room?
Hempcrete adds solidity as well as insulation and thermal mass to a building. This means a Hempcrete building is unlike most timber structures. It has excellent sound dampening qualities, while at the same time having a sense of substantiality about it. The insulation value is expressed as thermal resistance at a given thickness. Our standard walls are 300mm thick. This gives a thermal resistance R = 3.75 @ 300mm. Expressed in terms of U-value this is around U = 0.25.
Hempcrete's in situ performance is considerably in excess of this however due to the effect of its micro-porous and breathable structure. This gives it additional hydrothermal properties unlike many synthetic and impervious insulation materials. It also makes it a healthy and comfortable building to be in. But the benefits of Hempcrete don't stop there! It also has considerable thermal mass which helps to buffer temperature changes outside. This means it stays cool in summer as well as warm in winter so you can enjoy all year comfort in your garden room. Rather than thinking of your Freistaat Garden Room as a glorified shed, you should think of it as a genuine, independent, extension to your house.
How Is A Hempcrete Building
Different from A Normal Garden Room?
Hempcrete adds solidity as well as insulation and thermal mass to a building. This means a Hempcrete building is unlike most timber structures. It has excellent sound dampening qualities, while at the same time having a sense of substantiality about it. The insulation value is expressed as thermal resistance at a given thickness. Our standard walls are 300mm thick. This gives a thermal resistance R = 3.75 @ 300mm. Expressed in terms of U-value this is around U = 0.25.
Hempcrete's in situ performance is considerably in excess of this however due to the effect of its micro-porous and breathable structure. This gives it additional hydrothermal properties unlike many synthetic and impervious insulation materials. It also makes it a healthy and comfortable building to be in. But the benefits of Hempcrete don't stop there! It also has considerable thermal mass which helps to buffer temperature changes outside. This means it stays cool in summer as well as warm in winter so you can enjoy all year comfort in your garden room. Rather than thinking of your Freistaat Garden Room as a glorified shed, you should think of it as a genuine, independent, extension to your house.
How Much Will It Cost
To Build A Hempcrete Garden Room?
It's very hard to give a general figure but somewhere around £2,300/m2 will give you a 'ballpark' idea to work with. We are working on a standard range of designs and prices but at the moment every Garden Room is bespoke and so prices can vary from case to case. Get in touch and let us know what your requirements are and we can help you find out if a Freistaat Garden Room is right for you.
How Much Will It Cost
To Build A Hempcrete Garden Room?
It's very hard to give a general figure but somewhere around £2,300/m2 will give you a 'ballpark' idea to work with. We are working on a standard range of designs and prices but at the moment every Garden Room is bespoke and so prices can vary from case to case. Get in touch and let us know what your requirements are and we can help you find out if a Freistaat Garden Room is right for you.
Does My Garden Room Require
Planning Permission?
Unlike Building Control Regulations which apply wherever you are, Planning Regulations can vary depending on whether you are in a more highly regulated area or not. Below are the basics but there may be situations where building control regulations apply where planning is not required, and where planning regulations apply but where building control does not. If in any doubt its best to check with either your local authorities or a planning consultant before proceeding with any building works. Building works that do not require planning permission are called permitted development. Any dwelling. will have a designated area that is considered within the curtilage of the dwelling for the purposes of permitted development. In rural areas with more land this area may not cover the whole of the property.
One part may be classed as residential land with permitted development rights while another may count as agricultural ground where different rules apply. But generally speaking if the area of land in question is a back garden then it's covered by the rules relating to permitted development. If you are in a national park, a conservation area, or any other designated area then the rules are different than if you are not. Anything within these limits is classed as permitted development.
Maximum eaves height = 2.5m Maximum overall height = 4m for a dual pitched roof, or 3m for any other roof, I.e. flat, pent, etc. If the outbuilding is closer than 2m to any boundary the maximum overall height is limited to 2.5m. In national parks the size of any outbuildings more than 20m from the house is limited to 10m2 The original unaltered house (as built) can have additions - including outbuildings that can cover up to 50% of the land around the original house.
These are all external measurements and areas relating to overall footprint of buildings. In the case of sloping sites the measurement is taken from the highest point of the ground the building stands on. So this should be enough to get you started. The information provided here is correct to the best of our knowledge, but it is up to the customer to check that all relevant permissions are in place.
If in any doubt we can get a planning consultant to advise for a fee, or you can use your own.
If you want to go beyond the limits of permitted development and apply for planning permission we can also refer you to a planning consultant, and if you really want something special we can recommend architects who can design something truly unique. We can also work to plans that you provide if you want to design things yourself. There are many possibilities!
Does My Garden Room Require
Planning Permission?
Unlike Building Control Regulations which apply wherever you are, Planning Regulations can vary depending on whether you are in a more highly regulated area or not. Below are the basics but there may be situations where building control regulations apply where planning is not required, and where planning regulations apply but where building control does not. If in any doubt its best to check with either your local authorities or a planning consultant before proceeding with any building works. Building works that do not require planning permission are called permitted development. Any dwelling. will have a designated area that is considered within the curtilage of the dwelling for the purposes of permitted development. In rural areas with more land this area may not cover the whole of the property.
One part may be classed as residential land with permitted development rights while another may count as agricultural ground where different rules apply. But generally speaking if the area of land in question is a back garden then it's covered by the rules relating to permitted development. If you are in a national park, a conservation area, or any other designated area then the rules are different than if you are not. Anything within these limits is classed as permitted development.
Maximum eaves height = 2.5m Maximum overall height = 4m for a dual pitched roof, or 3m for any other roof, I.e. flat, pent, etc. If the outbuilding is closer than 2m to any boundary the maximum overall height is limited to 2.5m. In national parks the size of any outbuildings more than 20m from the house is limited to 10m2 The original unaltered house (as built) can have additions - including outbuildings that can cover up to 50% of the land around the original house.
These are all external measurements and areas relating to overall footprint of buildings. In the case of sloping sites the measurement is taken from the highest point of the ground the building stands on. So this should be enough to get you started. The information provided here is correct to the best of our knowledge, but it is up to the customer to check that all relevant permissions are in place.
If in any doubt we can get a planning consultant to advise for a fee, or you can use your own.
If you want to go beyond the limits of permitted development and apply for planning permission we can also refer you to a planning consultant, and if you really want something special we can recommend architects who can design something truly unique. We can also work to plans that you provide if you want to design things yourself. There are many possibilities!
Does My Garden Room Need
Building Regulation Approval?
While it is the customers responsibility to check with their local authority whether either planning permission or building regulation approval is required there are a few basic principles that you can use as your guide. These may vary in National Parks, Conservation areas, or Areas designated as being of Outstanding Natural Beauty. Building Regulation Exempt Developments are as follows: The largest detached building you can build without Building Regulation approval is up to 30m2 internal floor area.
If the internal floor area of the building is between 15 & 30m2 then the building must be single story this means that no mezzanine or loft floor is permitted.
If the building is within one metre of a boundary then in order to maintain exemption from Building Control Regulations the building must be constructed out of substantially non combustible materials. This one metre rule includes anything like gutters, soffits or anything that is part of the building. One millimetre too close to the boundary and the building materials must be substantially non-combustible. Meaning the building must be constructed out of brick, block, concrete panel, steel frame and metal panel. Hempcrete will not contribute to a fire but will smoulder away. If it is rendered/plastered both sides it is to all purposes non-combustible, but it would be worth checking with local authorities since it is an un-common material and may be subject to different interpretations by different authorities.
If your building is more than one metre away from any boundary then there are no limits to what materials you can use to construct it.
For smaller detached buildings up to 15m2 there are different rules. Buildings not exceeding 15m2 internal floor area are not limited to being single story, and there are no restrictions on the types of materials even if within one metre of the boundary. The 15m2 internal floor area includes all floors including mezzanine or loft floors. So this means a wooden shed - for example can be built against a boundary provided it is no bigger than 15m2 internal floor area.
If an outbuilding fits all the criteria above it is exempt from Building Regulation Control. If the building is exempt then other features of it are also not subject to control, this includes such things as toilets, showers, boilers, or wood-burning stoves. If you are planning on heating the garden room then provided that your building is covered by an exemption as explained above you do not have to comply with Part L which deals with insulation - although it is always an important consideration in any outbuilding to make it a pleasant place to be all year round. (See our section of the unique properties of hempcrete as a material). Any work that involves connection to any services of the main dwelling will require Building Control notification and approval.
So if you are connecting to the house electrical supply the electrical installation must comply with part P and must be carried out by someone qualified under the competent persons scheme.
If you are connecting to the drainage system of the house then this means the work must comply with Parts H1 in the case of Foul drains, and H2 in the case of Wastewater treatment or cesspools, and H3 Rainwater drainage H3 where applicable. This work must comply with these regulations but is not notifiable since it is covered by the exemption.
If you want to connect hot or cold water from the house then the work must comply with parts G1 cold water supplies. parts G3(2) and (3) Hot water regulations. This work is also notifiable.
Does My Garden Room Need
Building Regulation Approval?
While it is the customers responsibility to check with their local authority whether either planning permission or building regulation approval is required there are a few basic principles that you can use as your guide. These may vary in National Parks, Conservation areas, or Areas designated as being of Outstanding Natural Beauty. Building Regulation Exempt Developments are as follows: The largest detached building you can build without Building Regulation approval is up to 30m2 internal floor area.
If the internal floor area of the building is between 15 & 30m2 then the building must be single story this means that no mezzanine or loft floor is permitted.
If the building is within one metre of a boundary then in order to maintain exemption from Building Control Regulations the building must be constructed out of substantially non combustible materials. This one metre rule includes anything like gutters, soffits or anything that is part of the building. One millimetre too close to the boundary and the building materials must be substantially non-combustible. Meaning the building must be constructed out of brick, block, concrete panel, steel frame and metal panel. Hempcrete will not contribute to a fire but will smoulder away. If it is rendered/plastered both sides it is to all purposes non-combustible, but it would be worth checking with local authorities since it is an un-common material and may be subject to different interpretations by different authorities.
If your building is more than one metre away from any boundary then there are no limits to what materials you can use to construct it.
For smaller detached buildings up to 15m2 there are different rules. Buildings not exceeding 15m2 internal floor area are not limited to being single story, and there are no restrictions on the types of materials even if within one metre of the boundary. The 15m2 internal floor area includes all floors including mezzanine or loft floors. So this means a wooden shed - for example can be built against a boundary provided it is no bigger than 15m2 internal floor area.
If an outbuilding fits all the criteria above it is exempt from Building Regulation Control. If the building is exempt then other features of it are also not subject to control, this includes such things as toilets, showers, boilers, or wood-burning stoves. If you are planning on heating the garden room then provided that your building is covered by an exemption as explained above you do not have to comply with Part L which deals with insulation - although it is always an important consideration in any outbuilding to make it a pleasant place to be all year round. (See our section of the unique properties of hempcrete as a material). Any work that involves connection to any services of the main dwelling will require Building Control notification and approval.
So if you are connecting to the house electrical supply the electrical installation must comply with part P and must be carried out by someone qualified under the competent persons scheme.
If you are connecting to the drainage system of the house then this means the work must comply with Parts H1 in the case of Foul drains, and H2 in the case of Wastewater treatment or cesspools, and H3 Rainwater drainage H3 where applicable. This work must comply with these regulations but is not notifiable since it is covered by the exemption.
If you want to connect hot or cold water from the house then the work must comply with parts G1 cold water supplies. parts G3(2) and (3) Hot water regulations. This work is also notifiable.
How Do I Order My
Freistaat Garden Room?
Step 1: To enquire about our Garden Rooms contact us for a quick chat, or email us, about your requirements and we'll send you our questionnaire to fill out. In it we'll ask questions about size, design, services - such as electric and water, etc. Don't worry if you can't fill out everything as we can discuss many questions going forward as we firm up the design.
Step 2: Once we have hashed out the basic design - which is all free of charge - we can give an estimate of price to get the ball rolling and if you are still interested, we will arrange a meeting to go over details.
Step 3: We will then produce a 3D model of your proposed building for you to check over the design and make any adjustments. There is a design fee of £300 for this part as it is a few days work involved in doing the 3D model and every Garden Room is different. We will also finalise any more details still to be decided on the questionnaire form.
Step 4:Once we have all the details and a design that you are happy with then we will give you a firm price for the proposed works and a detailed breakdown of what is included in this price.
Our design fee will cover the structure and design configuration from a basic design point of view to make sure the costings can be accurately calculated and the design will work structurally. The 'look' of the building will be largely down to you to create.
Alternatively if you don't feel confident coming up with your own design, or if you want something extra-special and really want to make an architectural statement then we can put you in touch with our own highly talented architects who will be happy to design something. Or if you have your own detailed architect's drawings we can work from those.
How Do I Order My
Freistaat Garden Room?
Step 1: To enquire about our Garden Rooms contact us for a quick chat, or email us, about your requirements and we'll send you our questionnaire to fill out. In it we'll ask questions about size, design, services - such as electric and water, etc. Don't worry if you can't fill out everything as we can discuss many questions going forward as we firm up the design.
Step 2: Once we have hashed out the basic design - which is all free of charge - we can give an estimate of price to get the ball rolling and if you are still interested, we will arrange a meeting to go over details.
Step 3: We will then produce a 3D model of your proposed building for you to check over the design and make any adjustments. There is a design fee of £300 for this part as it is a few days work involved in doing the 3D model and every Garden Room is different. We will also finalise any more details still to be decided on the questionnaire form.
Step 4:Once we have all the details and a design that you are happy with then we will give you a firm price for the proposed works and a detailed breakdown of what is included in this price.
Our design fee will cover the structure and design configuration from a basic design point of view to make sure the costings can be accurately calculated and the design will work structurally. The 'look' of the building will be largely down to you to create.
Alternatively if you don't feel confident coming up with your own design, or if you want something extra-special and really want to make an architectural statement then we can put you in touch with our own highly talented architects who will be happy to design something. Or if you have your own detailed architect's drawings we can work from those.
Get In Touch
With Us.
FREISTAAT GARDEN ROOMS ARE MADE FROM HEMPCRETE.
A modern bio composite, combined with a timber structure of standard 4x2 studwork, with optional Oak Frame details.
Get In Touch
With Us.
FREISTAAT GARDEN ROOMS ARE MADE FROM HEMPCRETE.
A modern bio composite, combined with a timber structure of standard 4x2 studwork, with optional Oak Frame details.