FREQUENTLY ASKED QUESTIONS

HEMPBUILD LTD. SUPPLY SUSTAINABLE CONSTRUCTION MATERIALS WORLDWIDE

Hempcrete blocKs FAQ’s

A list of commonly asked FAQ’s relating to Hempbuild’s Isohemp Hempcrete Products and associated materials. Hempbuild Isohemp hempcrete blocks are great for glued, non-load-bearing masonry for building healthy, natural insulation and partition walls. It is a versatile product recommended by professionals for both new builds and renovations, from complex restorations to extensions, family homes, community buildings and commercial buildings.

If you have a question that you cannot find the answer to, please contact us – we are more than happy to assist.

The Hempbuild Isohemp hempcrete block consists of hemp, hydrated lime and hydraulic lime. They are 100% natural and locally sourced raw materials.

They are non-toxic and resistant to mold, pests, and fire, making it a good choice for both new build construction and an excellent choice for a healthy home.

Yes, Hempbuild Isohemp hempcrete blocks are associated with a load-bearing structure to create envelopes for new constructions. Several possibilities are possible: wooden construction, load-bearing blocks or the IsoHemp Hempro system.

Yes, Hempbuild Isohemp hempcrete blocks allow the interior to be renovated by keeping the inertia of the building and allowing the old walls to breathe. They are particularly suitable for the interior insulation of old brick or stone walls.

Yes, Hempbuild Isohemp hempcrete blocks allow the interior to be renovated by keeping the inertia of the building and allowing the old walls to breathe. They are particularly suitable for the interior insulation of old brick or stone walls.

The interior finishes are varied: indoor ceiling, clay, tiles, wood cladding, etc. PCS plaster, a natural render based on natural plaster, lime and sand ideal for finishing your walls and ceilings with a very smooth finish.

The exterior finishes are varied: siding, plaster, bricks or briquettes, etc.

The hemp block has a length of 60 cm and a height of 30 cm. Only its thickness varies: 6 cm, 9 cm, 12 cm, 15 cm, 20 cm and 30 cm.

There are 6 thicknesses: 6 cm, 9 cm, 12 cm, 15 cm, 20 cm and 30 cm.

The maximum weight of a Hempbuild Isohemp hempcrete block varies according to the thickness and humidity content :

  • Block of 60 mm: 4.6 kg
  • Block of 90 mm: 7.1kg
  • Block of 120 mm: 9.2kg
  • Block of 150 mm: 11.5kg
  • Block of 200 mm: 15.3kg
  • Block of 300 mm: 23kg

No, Hempbuild Isohemp hempcrete blocks are not load-bearing. They must be used in tandem with a supporting structure. Several construction systems can be used: the Hempro system, wooden frame, post-beam system, or supporting masonry.

  • However, it is self-supporting up to 10 metres high depending on its thickness.

The Hempbuild Isohemp hempcrete blocks are laid in a thin joint with a natural adhesive mortar. This is a lime-based mortar that is used instead of traditional mortar. The installation is done in a thin joint of around 3 mm using a glue comb or a notched trowel.

The Hempbuild Isohemp hempcrete blocks are laid in thin joints around 3 mm thick.

Several cutting tools can be used :

  • A Widia manual saw blade;
  • An electric Alligator saw;
  • A band saw (recommended for larger sites).

Yes. Whether it’s a renovation or a new construction, the use of Hempbuild Isohemp hempcrete blocks on the ground makes it possible to insulate the slabs and is suitable for supporting a screed. This technical solution is fast and simple. The placed product is dry, which makes it possible to apply the finish very quickly.

Two systems exist for insulating your ground with hemp blocks:

  • Slab – block – screed
  • Draining mass (telford base) – stabilised – block – screed
  • Excellent compressive strength (15 T/m2).
  • Speed of execution and performance over time.
  • High technical flexibility such as the application of floor heating, the application of ducts in the screed, etc.
  • Easy and fast cutting.
  • Laying of insulation in just a few hours for a complete house.

Hemp blocks can only be placed on flat roofs. For the insulation of flat concrete roofs, it’s very easy to install hemp blocks. Whatever the configuration, they are fast and easy to apply. Slope concrete is applied on which the waterproofing of the roof is then laid.

This solution has the advantage of quick and easy implementation on site. With its high thermal inertia, the Hempbuild Isohemp hempcrete blocks prevents overheating of the building in summer and guarantees excellent resistance over time.

Yes. To make grooves for electricity or other technical networks, it’s recommended to use a grooving machine and a suitable hole saw.

The lambda (= thermal conductivity) of an IsoHemp block is 0.071 W/mK.

The specific heat of the Hempbuild Isohemp hempcrete blocks is 1600 J/KgK.

The density (= dry apparent mass density) is 340 kg/m³.

As long as the building exists and the Hempbuild Isohemp hempcrete blocks is protected by a finish (plaster, brick, etc.), it will not degrade and its technical performance will remain intact.

For situations where thermal and acoustic insulation is required, it’s essential to render the Hempbuild Isohemp hempcrete blocks. They are not airtight and it’s the block + rendering system that creates the technical performance. For applications where maximum sound absorption is desired, it’s possible to paint the wall directly using a spray gun or to attach a fixator to the wall.

Hempbuild Isohemp hempcrete block pallets can be stored outside for 3 months and stored for 2 years if the pallets are covered and protected from rain.

Hempbuild Isohemp hempcrete blocks are suitable for all types of projects. In addition, they guarantee the success of your project and have many advantages such as:

  • Thermal and acoustic performance essential to comfort.
  • Natural regulation of humidity.
  • Flexible design.
  • Long-term durability.
  • Ease of implementation.
  • A wide choice of finishes: brick, parging, cladding, etc.

Hempbuild Isohemp hempcrete blocks are particularly suitable for the construction of residential houses, doubling of existing walls on the inside or outside, as well as industrial subdivision and apartments.

One week after laying the Hempbuild Isohemp hempcrete blocks if the wall is dry.

This gluing technique is used only for the implementation of Hempbuild Isohemp hempcrete blocks with 6 cm thickness. The gluing of the blocks is done only against an existing uniform and flat wall. It is recommended to use a special bonding mortar that is suitable for the gluing substrate according to the manufacturer’s instructions. Do not use bonding against a wooden element.

Yes it is possible.

Hempbuild Isohemp hempcrete blocks cannot be placed on the ground directly. It is necessary to provide a foundation with a rotproof insulating block between 15 and 30 cm thick according to the stability calculations before laying the hemp blocks.

From 3 cm, it’s recommended to fill the gap with a mixture of ProKalk lime and hemp and a little water.

After three courses, it’s recommended to wait between 1 and 2 hours before resuming the masonry work.

The wall is dry after one week if it’s placed in good conditions. The state of the wall depends on the state of the blocks during the implementation. If the blocks have been wetted by rain before implementation, the drying of the wall will take longer.

Dual flow ventilation is not required when using Hempbuild Isohemp hempcrete blocks. Ventilation is nevertheless essential to ensure correct air renewal, because if the blocks are open to water vapour and rendered, they become airtight.

Hempbuild Isohemp hempcrete blocks are not implicated in any risk of allergies. In case of risk, be sure to use a primer and a completely natural paint as a finish.

120 Hempbuild Isohemp hempcrete blocks.

78 Hempbuild Isohemp hempcrete blocks.

60 Hempbuild Isohemp hempcrete blocks.

48 hempcrete blocks.

36 Hempbuild Isohemp hempcrete blocks.

24 Hempbuild Isohemp hempcrete blocks.

ISOHEMP HEMPRO SYSTEM FAQ’s

The IsoHemp Hempro system is a method of loadbearing for hempcrete block walls. The system consists of Hempbuild Isohemp hempcrete blocks that have been specially adapted to allow the casting of a reinforced concrete frame inside the hempcrete wall which will then support the construction and roof.

  • Speed of implementation.
  • Homogeneity of the wall: only one product.
  • A healthy and natural product.

The Hempro system can be used for low-energy, very low-energy and passive buildings.

PCS INTERIOR PLASTER FAQ’s

PCS interior plaster is an economical, durable and superior solution. The interior plaster is a well-judged mix of natural plaster, limestone and sand. Ideal to coat your walls and ceilings both for renovations and new builds. It combines the easy application of natural plaster with the benefits of limestone, such as the natural moisture regulation of the living space in your home or building.

The Hempbuild Isohemp hempcrete block consists of hemp, hydrated lime and hydraulic lime. They are 100% natural and locally sourced raw materials.

They are non-toxic and resistant to mold, pests, and fire, making it a good choice for both new build construction and an excellent choice for a healthy home.

No, Hempbuild’s Isohemp PCS interior plaster is a primer exclusively reserved for indoor applications.

Between 10 and 20 mm.

  • A primer open to the diffusion of water vapour.
  • A healthy, natural and sustainable product.
  • An economical solution.
  • A smooth and ready-to-paint finish.
  • Ease of implementation.

One week after laying the hempcrete blocks if the wall is dry.

Yes, Hempbuild’s Isohemp PCS interior plaster is a 100% natural product that is not harmful to health.

Hempbuild’s Isohemp PCS interior plaster provides a white finish that is smooth, modern ready to paint.

ADHESIVE MORTAR FAQ’s

A natural adhesive for Hempbuild’s Isohemp hempcrete blocks. An adhesive mortar that has been specially developed for the implementation of construction using hempcrete blocks for interior and exterior use. It is a lime based mortar that is used in place of traditional mortar, applied as a thin seal of approximately 3mm by using a dedicated adhesive comb or trowel.

It’s a mortar based on lime.

Yes, adhesive mortar is a 100% natural product.

The hempcrete block installation is done in a thin joint of around 3 mm using a glue comb or a dedicated trowel.

The average consumption is 2 bags per pallet of hempcrete blocks.

The drying time of adhesive mortar is 36 to 72 hours.

The usage time is one hour.

The average consumption is 2 bags per pallet of hempcrete blocks.

There are 40 bags per pallet.

MISCELLANEOUS FAQ’S

Miscellaneous questions relating to various hempcrete construction questions and also certifications.

Isohemp maximise the short route and have different suppliers in Belgium, France and the Netherlands.

It is recommended to use IsoHemp lintels. IsoHemp lintels are prefabricated hemp concrete lintels with a reinforced concrete core used for opening doors and windows in hemp block masonry. They are perfectly suited to new constructions and interior or exterior renovations.

With an excellent fire reaction (class B for the rendered block), they offer up to 2+ hours of fire resistance depending on the finish and the thickness of the block used.

It is recommended to use IsoHemp lintels. IsoHemp lintels are prefabricated hemp concrete lintels with a reinforced concrete core used for opening doors and windows in hemp block masonry. They are perfectly suited to new constructions and interior or exterior renovations.

No, Isohemp are manufacturer’s and do not sell direct. Hempbuild Sustainable Products Ltd are a major distributor who have our products in stock.

Yes, we have a technical approval issued by CSTC for IsoHemp hemp blocks. You can downloaded it in our technical documents section.

Yes, the manufacturer Isohemp have indeed conducted a Life Cycle Analysis on the products and on their manufacturing process.

This analysis identified the stages of the Life Cycle where the main impacts of Hempbuild’s Isohemp hempcrete blocks occur and validated the positive carbon balance of the hempcrete blocks.

The impact in the Global Warming category has a value close to -100kg of CO2 stored per 1m3 of hemp blocks. This negative value indicates long-term CO2 storage that is beneficial to the environment. This LCA can be consulted and downloaded in our technical documents section.