Stop Moisture and Condensation In The House

What You Should Know About ICF

A guide by the Insulating Concrete Formwork Association


What about the problems with condensation and damp?

You cannot ignore the problems that continuous moisture brings for occupants. A home filled with moist air can suffer from musty odours, damage on walls and ceilings, mildew and worst of all trace of mould.

The problem is so bad that the latest study from UKCMB, the UK Centre for Moisture in Buildings, recorded that “moisture problems have worsened over the past five years. In the UK this mostly “down to poor monitoring and maintenance, irrespective of era or construction type”.

Most concerning of all are the significant health effects it can cause, particularly for the young and elderly. According to the NHS, you are “more likely to have respiratory problems, respiratory infections, allergies or asthma” since the damp and mould can “produce allergens (substances that can cause an allergic reaction), irritants and, sometimes, toxic substances”.

This is where choosing a build solution like ICF can make a real difference, providing opportunities to improve the quality of the environment within the building, bring with it potentially significant improvements in the health and well-being of the occupants.

Why Does Moisture and Condensation Form In Buildings?

Inside the home, everyday chores and activities cause moisture to occur. Whether that’s mopping your floor, hanging laundry inside or just having a nice hot shower at the end of the day, they all impact on humidity levels in your home. The problem can be made worse depending on the internal temperature. The amount of water vapour in the air will increase, as the internal temperature increases.

When the vapour meets a cold surface, it creates condensation in the house. For example, when taking a relaxing hot shower, it creates lots of moisture in the air in the form of steam. When it encounters your wall, which is typically colder, it condenses to water creating an ideal environment for mould to form.

Condensation in the house

How To Avoid Moisture and Condensation In The House?

Insulation

Reduce the number of cold surfaces by increasing the amount of insulation. However, raising the insulation levels may in fact acerbate the issue, which is why it is important to add in methods of ventilation.

Airtightness

An airtight structure not only improves the energy efficiency of your home, but it also aids in stopping the exchange of different air temperatures between indoors and outdoors. After all, when new air enters the building, you will need to heat or cool it to the same level as the indoor temperature to limit condensation.

Can ICF Buildings Decrease Moisture and Condensation In The House?

High levels of thermal performance – With ICF, the blocks are made from two layers of an insulating material which are stacked to create the wall structure. Concrete is poured into a central cavity within the block, allowing it to sit in direct contact with the insulating block to create a monolithic and solid structure. The end result, if designed and installed correctly, is a building that offers exceptionally low U-values and excellent thermal mass and an, even, stable temperature throughout the home.

Providing superior airtightness and prevents thermal bridging – The concrete in the core of the building has a high storage capacity which, combined with low thermal conductivity, stabilises temperature fluctuations between the outside and interior of the building to minimise condensation and mould. Be aware that as an airtight structure, your designer will need to have a clear understanding on how to effectively ventilate the structure. Solutions include installing a Mechanical Ventilation Heat Recovery (MVHR) system to keep humidity at a perfect level.

Will ICF Blocks Rot

Other Steps To Controlling Moisture and Condensation In The House

To make sure your ICF home maximises its control of moisture levels, there are a few areas to consider.

Firstly, choose weatherproofing cladding which will further protect your ICF system water ingress and moisture issues. This could be brick, render, or timber, depending on your preference. Each type of cladding will have specific requirements that must be addressed, such as maintaining a nominal 50mm clear drained cavity between the ICF system and the brick or stone outer leaf.

For those that live in areas where moisture is typically prone to seeping into a structure, such as the end of a cliff edge or next to a quarry, we recommend installing a waterproof system. Many of our members will use a peel-and-stick membrane which consists of a bitumen layer on one side and a woven composite for UV protection on the other. It can either be applied directly to the surface the face of the wall, or with a primer over the entire wall.

Make sure your windows and doors are properly aligned and fitted to maintain an airtight building and prevent cold air entering through gaps. Remember, with an airtight structure you typically need an MVHR to remove humidity within the building.

Why Choose An ICF System From An ICFA Member?

The best way to prevent moisture and condensation in the house is to make sure you have a well-experienced supplier you can trust which is why we recommend working with our ICFA members. They have the expertise and knowledge that can provide you with peace of mind. Most importantly, getting them involved early in the design process can help avoid potential issues (e.g., inadequate ventilation) from arising.

Contact Us

Interested to find out more about how ICF can help with moisture problems? Get in touch today!