Roofing decisions: Relative Cost Increase Vs. Cost Totality

When selecting roofing materials for a building project, taking a price-led approach per unit cost may not be the best approach. Pauline Manley, Marketing Director at Klober, explains how this can create a false economy and that cost totality of a project is defined by more than the up-front cost.

There is a common misconception that value-engineering of products, to make initial savings, will provide greater value in the long run. When it comes to roofing, it is particularly pertinent to realise this is not always the case. In reality, choosing premium roofing options will not raise the overall build cost by as much as might be expected, when directly compared with the cost totality of a project.

Getting it right first time

With routine maintenance, a good roofing system should last for decades. It is highly concerning therefore that there are many developments falling short. Numerous reports can be found of newly-installed roofs, or ones that are only a few years old, that are falling apart, leaky and dangerous. It is therefore really important to get roofing right first time, especially as the housebuilder is generally contractually responsible to make repairs in the first year.

Don’t go by price alone

The old saying ‘you get what you pay for’ does hold a grain of truth. While cheaper products can do the job, it is important to be aware that the difference between underlays is not just fiscal, but can also be vast in terms of performance.

As membranes have become more technical and specific in design over the years, many manufacturers have invested in rigorous product testing to ensure that underlays meet the requirements they claim. Tested products may come with a higher price tag because they claim bolstered strength and

durability which is verified by trusted industry bodies. The National House Building Council (NHBC), for instance, will only accept certain breathable membranes without additional ventilation if they have relevant British Board of Agrément (BBA) approval.

Breathable membranes, especially ones that are both vapour and air permeable, are the best type of underlay for developments that want to benefit from reduced risk of condensation. Because new homes tend to be more air tight and at a greater risk of condensation, this is a particular concern. While this type of membrane will be more expensive than a non-breathable membrane, because breathable options have less vapour resistance, this allows water vapour to exit freely without the need for separate ventilation above the roofing insulation.

Doing the math

In practice, when using a typical 150sqm roof, an average of three rolls of underlay would be required. The average cost saving achievable for three rolls of budget underlay will only recoup a few hundred pounds at the most, in lots of cases however the saving will be dramatically less than this. When considering the whole building project, the value of spending a fraction more to achieve better results at a cost-level of this scale makes sense. The time saving benefits of using premium products, designed with ease-of-installation as well as exceptional performance in mind, also adds further value for the installer by reducing the time spent on site.

Raising the roofing standard 

In order to continue raising the roofing standard, cost cannot be a sole consideration. It is possible to prioritise performance and longevity of the roof and still meet the project requirements in terms of budget and timeframe. With a slightly higher investment, there can be significant time and cost savings down the line.

For further information please visit