When deciding how to build your house, cost will be a factor, so is blockwork still cheaper than timber frame? We delve into the stats.
In this article we cover:
- ICF, blockwork and timber frame examples
- Rules of thumb to make comparisons
- Main pros and cons of each
Is it still cheaper to build out of blockwork or is timber frame and Insulating Concrete Formwork (ICF) on par now with building regulations being so tight?
Keith Says: It depends on the design, and what factors you take into consideration, but as a rule of thumb traditional methods remain more cost effective.
The answer to this, like many other questions, will vary much come down to the design and layout of the building. Some forms of construction will be more suited to others and costs will fluctuate depending on that design.
In a general context we carried out a review of ICF versus blockwork on a recent house in northside of Dublin which had over 1,500sqm of external wall blockwork. The ICF supplied and fitted cost we received was €180 per sqm which resulted in a total cost of the structure of just over €270,000 (yes, it’s a large house).
When we compared this back to the traditional blockwork cost (we excluded the external render from our calculations), we had circa €114,000 of blockwork costs, €27k of lintel and thermal block costs, circa €41k of insulation and DPC costs and then circa €45k in the need for an airtightness membrane, so an overall cost of circa €227,000.
It is for other people to decide which route is better from a building regulation perspective, the tradtional route is still a cheaper option, with the main differential driven by the cost of ready-mix concrete.
The main area that ICF sets itself apart from the traditional route is the speed of installation and reduction in waste. There is very little waste from an ICF installation compared to the traditional route.
There can be no doubt that when it comes to detailing, quality control, cavity maintenance, thermal bridging and the likes, traditional construction will struggle to match the abilities of ICF, but on a purely cost basis, ICF has a way to go to take that issue of the deciding table.
In respect to timber frame, outside of the clear benefit in speed on installation, I have never found that it is comparable with the costs of traditional construction, mainly due to the fact that most people still install an outer skin, which is generally done in blockwork or brickwork anyway which results in the need for scaffolding, blockwork and mortar in any event.
