Without The Right Insulation, Your Flat Roof is Burning Money – Every Month
Crazy as it sounds, most older flat roofs in the UK have little or no insulation. So every time the heating goes on, heat – and money – disappear through the rooftop!
If your flat roof is in that state, the good news is…we can put it right.
It will take some work, though. It’s not as simple as showing up with rolls of insulation and laying them in the roof. We need to look at the spec first, and take some remedial steps.
So – what type of roof are we looking at?
If it’s an old-style roof that hasn’t been touched for years…
You might have some basic rock wool insulation fitted between the joists. And chances are, there are ventilation gaps to let air flow through the roof.
This is an old method known as a COLD ROOF. It’s designed to blow away the condensation that forms on the structural deck - just like switching on your car’s air-con to blast away mist from the windscreen.
It’s all good in theory. But in practice, it causes more problems than it solves:
…The basic insulation gives very little protection. Heat escapes quickly.
…The ventilation gaps allow cold air to blow downwards, chilling the space below.
…Inside the roof, cold and warm air streams merge and turn to liquid. Condensation follows.
…Most of the condensation gets blown out by the air flow. But some of it clings on, and eats away at the timbers.
…Meanwhile, the roof has become a breeding ground for black mould and spores – a serious health hazard that needs to be treated urgently.
In other words, this outdated insulation method –
• Makes the roof vulnerable
• Raises your heating bills
• And puts your family at risk
That’s far from ideal! So these days, there’s a better way…
The new-style WARM ROOF
A Warm Roof uses solid PIR insulation boards that sit above the roof deck, topped by moisture-tolerant boards. This changes the ‘Dew Point’ where warm and cold air streams merge and turn to liquid.
This way, moisture is isolated before it can reach the deck - meaning condensation can’t form and weaken the structure.
As a result, there’s no need for ventilation gaps. They can be sealed, so there’s no downward draft and no way for warm air to escape.
So - once you convert from a cold to a warm roof, your heating bills will plummet!
What if it’s a newer roof?
Insulation problems are not confined to older roofs. New roofs have their troubles too – if they’re built by amateurs, who won’t take the trouble to install a Warm Roof.
A rogue roofer, for example, will skimp on insulation to save on costs. Often, they’ll leave it out altogether – and tell you it’s a “luxury extra”!
And cowboys, who botch through ignorance, are no better. They’ll leave you with basic rock wool, or sub-standard boarding.
Triggering draughts and condensation…all those problems again.
So what insulation do you need?
Whatever state your roof is in today, the end goal should be an insulated roof that meets the government’s insulation targets.
It makes sound economic sense. And it’s part of a legal requirement if you’re building a new roof - or refurbishing at least 50% of a roof that sits over a living space.
So any work we do for you will comply with Part L of the 2010 Building Regulations: Conservation of Fuel and Power.
There’s a lot of confusion around this, so it deserves an explanation.
The government wants to limit every property’s impact on the environment. So targets are set around “U-Values” – the measurement used to score building materials for energy efficiency.
A low U-Value is good, as it means less energy escapes. So your roof has to meet – or fall below – a maximum U-Value.
The rules state:
- If the roof is already insulated, the maximum U-Value is 0.20
- If you’re insulating from scratch, the maximum U-Value is 0.18
- If compliance is a challenge, due to weight loading or height restrictions, the U-Value might be relaxed to a maximum 0.35
You can’t meet these targets with a Cold Roof using traditional rock-wool!
You’d need 120mm to achieve a U-Value of 0.20. So in a typical flat roof, you simply won’t have enough space.
But with a Warm Roof, it’s easy.
PIR boards are high in density. With the right spec and fitting, they’ll achieve a U-Value as low as 0.11, with room to spare in the roof.
Keeping you well below the threshold, so your roof is fully compliant.