Breathable Building.
Breathable building materials, with the evidence.
Traditional English brick terrace with a lime-rendered section, sash windows and lime-pointed masonry

A field guide to breathable materials

Breathable building materials, with the evidence.

Plain-English research on lime mortar, lime render, breathable plaster and heritage construction. Every claim cited to gov.uk, Historic England, and UK trade standards.

Read the first guide

Why breathable materials?

Traditional UK buildings (pre-1919 solid walls, listed properties, lime-built structures) need materials that let moisture move through the wall. Seal them with cement, gypsum, or modern paint and you trap damp inside. That leads to decay, mould, and expensive remedial work.

This site gathers the research on lime mortar, lime render, lime plaster and compatible finishes, translates the jargon, and cites the primary sources so you can make informed decisions for your own project.

Sources we cite

  • Historic England
  • SPAB
  • Building Research Establishment
  • Building Limes Forum
  • British Standards (BS EN)
  • gov.uk

Browse the specimens

Four material families, each with its own hub of guides.

01 Freshly applied lime plaster on a solid brick wall

Lime plaster

5 guides

Breathable internal finishes for heritage walls. NHL hydraulic limes, lime putty, and when lime plaster beats gypsum.
02 Textured lime render on a traditional exterior wall

Lime render

5 guides

External rendering with breathable lime. Mix ratios, three-coat application, and protecting soft masonry.
03 Traditional lime mortar joints in heritage brickwork

Lime mortar

4 guides

Lime mortar for repointing and building. NHL grades, mix ratios, and why cement damages old brick.
04 Limewashed wall in a soft natural finish

Lime paint

2 guides

Breathable paint for lime-plastered and rendered walls. Limewash, mineral paint, and protecting historic finishes.