| Sustainable Energy Ireland (SEI) currently operates | | | | may not have any insulation. |
| two home energy conservation programs where the | | | | A sure giveaway sign is the brick pattern of the |
| participant house owners may be reimbursed the | | | | exterior wall. In general wall bricks are laid in 3 |
| total cost they incur while carrying out certain home | | | | patterns. viz; |
| energy improvements. One such improvement is the | | | | - Stretcher bond |
| cavity wall insulation. Cavity walls provide a | | | | - Flemish bond |
| convenient structural design to support wall insulation | | | | And, |
| material. | | | | - English bond |
| Cavity Walls | | | | Of these only the stretcher bond patterned brick |
| Cavity walls are external building walls which | | | | walls will have a wall cavity. A stretcher bond |
| incorporate an air gap which may be within the wall | | | | patterned brick wall will have the bricks laid flat on |
| structure itself (for e.g. Hollow block walls) or | | | | side and in a linear manner i.e. bricks laid end to end. |
| between two solid walls (or between two partitions | | | | Another tell tale sign is the width of the total wall. |
| having a narrow air gap separating them).The latter | | | | Due to the incorporated cavity the width is in excess |
| technique was widely used in houses constructed | | | | of the normal 300 mm width you would expect it to |
| between 1932 to 1982. | | | | have. |
| Almost all houses constructed after 1982 adopted | | | | It is always better to get a skilled person with proper |
| the cavity wall technique with or without the use of | | | | tools to give advice on these matters. Normally they |
| insulation. | | | | drill holes in the wall and collect data to find out the |
| Why do you need insulation in cavity wall? | | | | details of the air gap, insulation material (if any), and |
| The wall cavity maintains an air gap which is a good | | | | the present condition of it. |
| insulation. (In fact it is about the best available | | | | Types of insulation for cavity walls |
| conveniently and almost all other manufactured | | | | The commonly used materials are; |
| insulation material incorporates air bubbles or spaces in | | | | - Fibreglass or mineral wool with short strands |
| order to gain this advantage).When the cavity width | | | | - Cellulose loose fill or stabilized cellulose |
| between the two walls exceed a certain critical | | | | - Phenolic and other Synthetic foam cavity board |
| dimension the air within the gap start moving about | | | | –(Used in new constructions only). |
| due to convection (convection currents) which start | | | | Cavity wall insulation if it is a retrofit in an existing |
| assisting heat transfer from the warmer to the | | | | house will not take more than 3 or 4 hours. Of |
| colder side rather than blocking it. | | | | course it has to be handled by a skilled person with |
| Porous insulation fill will restrict the air movement | | | | specialized tools. They would drill holes in the existing |
| within the cavity providing optimized insulation quality. | | | | external wall at regular intervals, insert a special |
| How to find out whether your house has cavity walls | | | | nozzle and blow short strands of insulation material in |
| All houses built during the last 25 years are almost | | | | to the wall cavity. If the house is being constructed |
| certain to have cavity walls. It is possible these may | | | | anew phenolic foam rigid board or expanded |
| be insulated too. Houses built during the 50 years | | | | polystyrene foam boards too may be used. |
| prior to that are also likely to have cavity walls but | | | | |