BREATHABILITY
           
 

What is Breathability? The materials and the techniques used in the construction of period properties rely on the principle of allowing moisture to pass through them when necessary – this is known as breathability. Period properties are built using the principle that they will allow moisture to pass through them.

 
           
       
           
  Modern buildings are built using the principle of preventing any moisture entering them. To do this they are constructed using modern, impervious materials and adopt modern building methods such as damp proof membranes to completely exclude moisture from a property.  
           
Plastic Bag Theory. A good analogy to display how breathability works in old buildings is to witness the effects that occur when you place your hand in a plastic bag for a period of time.  
The hand represents the breathing Period Property and the plastic bag represents the impervious nature of modern building materials
   
As your hand tries to breath and release moisture, the moisture is trapped and prevented from escaping by the impervious plastic bag. A build up of moisture forms on the inside of the plastic bag
 
 
 
How can you stop the build up of moisture and the suffocation of your hand? Will placing a second plastic bag over the first stop this? It will certainly stop any moisture from the outside entering. However, just like in the case of a Period Property, we are dealing with moisture trying to escape
 
 
 
The only way to help your hand breath is to remove the impervious plastic bag(s). This is exactly how we should deal with the breathability requirements of Period Properties - remove impervious materials
 
 
 
     
 
Why is Breathability Important? Excessive moisture trapped inside a natural material such as timber, brick or stone will lead to its decay. Breathability - the ability of a natural material to allow moisture to pass through it is essential to maintain normal, acceptable levels of moisture and therefore avoid decay.
  
     
 
Which Materials are Breathable? All natural materials such as Timber, Brick, and Stone are breathable. Period Properties were all constructed using Lime as the principle raw material for producing mortars, plasters, renders and colour washes The use of lime allows natural materials to be used whilst maintaining breathability.
  
     
 
Which Materials are not Breathable? Modern materials such as cement, gypsum and modern paints are impervious and therefore do not allow the breathability and flexibility required by the natural materials used in Period Properties.
 
     
 
How can Breathability be Maintained? Simply by removing all modern materials whenever possible and replace where necessary with a breathable traditional alternative.