Hessian

Description

Hessian, sometimes referred to as Burlap, is a loose woven natural fabric made from fibres of the jute plant, it’s use is widespread in several industries. A very robust material that can withstand repeated wetting and drying without compromising its strength, and as such very common in the construction industry for the curing of concrete especially. In the context of lime mortars and renders, Hessian is (or certainly should be) your primary material of choice for their aftercare.

It is a very useful way to protect the mortar, acting as:

• a frost blanket during the colder months.
• a humidity cover when wetted down during the warmer months, preventing mortars from rapid drying out; one of the most common causes of failure in lime mortars.
• a wind break reducing the action of wind drying; all very important for the appropriate curing of lime mortars and renders.

Hessians are categorised by their weight, expressed as ‘gsm’ or grammes Per Square Metre with the lower number representing a more open weave to the fabric with less material used, hence it being lighter. Cornish Lime stock 3 grades: 229, 273 & 366 gsm (Grammes Per Square Metre). Available in full rolls measuring 50 x 1.8 Metres (151 x 6 feet) or by the metre cut from the roll, which will be slightly more expensive per meter.

229gsm – Summer Work: Thin material, won’t offer much protection from adverse weather but is suitable for keeping mortar damp when working in hot periods.

273gsm – All Around: Medium weight material, suitable for most applications.

366gsm – Winter Work: Thick material, offers excellent protection from frosts and adverse weather in the winter months.