ICFs are ideal for constructing basements; this simple method of construction eliminates the risks associated with other types of basement construction and reduces the building schedule.

Many ICF manufacturers have developed blocks specifically for constructing retaining walls below ground. The retaining wall blocks core thickness ranges from 210mm or 250mm. When building below ground less insulation is needed then for above ground as the soil backfill acts as an insulator significantly reducing heat loss through the walls.

The increased core thickness from allows for a greater mass of concrete within the structure making it far stronger; it also allows more steel reinforcement to be added but still allows the concrete to flow freely reducing the chance of voids or air pockets within the concrete core.

Denstone Construction are specialists in the waterproofing and tanking of both new and existing structures. We are accredited installers for Remmers UK a leading manufacturer of building products. We can tank basements retaining walls, balcony’s and floors.

We also use the latest concrete admixtures to waterproof ICF structures below ground. Xypex is a crystalline waterproofing agent which is added to the concrete during batching. The concrete is poured and vibrated to expel any air pockets and voids. A simple joint detail seals the concrete bonds between day joints. This method of waterproofing is extremely robust and cost effective, as it considerably reduces labour during installation.

Xypex is one of many types of waterproof concrete available today; we have used in conjunction with ICFs on basements, retaining walls and even an underground house.

The main benefits of using Xypex admixtures are:

• Impervious to liquids
• Speed of installation
• Minimal labour costs
• Extremely robust
• No protection of building required during backfilling
• No over excavation of the site
• Protects the concrete against chemical attack
• Remains dormant within the concrete ready to react and seal any cracks up to 0.4mm

There are many tanking systems on the market which are suitable for use on ICF buildings.

External tanking is widely agreed to be the best method for waterproofing new and existing structures where possible.

The main benefits of using exterior tanking systems are:

• Keeps the walls of the structure dry
• Extremely robust
• Flexible and allows for movements over day joints
• Easily repaired
• Easy installation of service ducts through tanking