Insulation in House Construction
Integral to modern house construction in the UK is insulation. It is used to achieve thermal resistance around the building creating comfort and economy.
Insulation properly installed will reduce heating costs by reducing heat loss.
Starting at floor level, it is now a requirement of the Building Regulations to insulate ground floors. The standard method is to lay sheets of polystyrene or similar above the ground floor and then lay a screed or a timber floor over.
But some systems incorporate insulation within the floor itself, underfloor insulation boards must be fully supported over their entire area with no voids and no projections. The silver foil covering acts as a vapour barrier or vapour control layer and also stops moisture from the freshly poured concrete slab penetrating the insulation.
The actual heat loss through the floor is considerably less than that of the walls or roof, but given the ease with which it can be utilised during building, it represents good value.
Polystyrene solid panels, or even on-site spray are another modern alternative.
As the walls begin construction sheets of slab insulation are fitted as the walls go up: a typical build process would be inner leaf first to one course over wall tie height; insulation; outer leaf to the top of the insulation; then continuation of the inner leaf. In both cases, the slabs are sized to fit between standard-spaced wall ties (usually 450mm or two block courses in height) in order to aid installation.
Partial-fill is the standard choice for most new developments. It involves leaving a 25mm or 50mm gap between the outer face of the insulation and the external leaf. This has the advantage of reducing the chance of any moisture that does penetrate the outer leaf bridging through to the internal structure. For that reason, the system is required in many building regulations.
Semi-rigid batts of glass mineral wool or rock wool are the traditional choice. Their flexibility allows them to fit snugly against the masonry as well as knit together at abutments.
A typical brick and block wall has a 150mm cavity and most rigid or semi-rigid panels inserted will give good returns.
The other major cavity wall insulation method allows for quicker overall construction time, but this blown-in method is does not perform quite as well.
The roof insulation is of great importance, as most roofs are “cold” roofs, which means that the lower surface of the loft space, that is, the horizontal joists to which the ceiling is attached underneath, will carry the insulation that prevents the rising heat from the rest of the house escaping. This is usually rolls of rock wool or polystyrene slabs or pellets.
Warm roofs are those roof spaces which are in used as a living space and the insulation therefore has to be installed directly under the roof in the plane of the roof’s pitch (slope). Insulation will reduce heat loss and your loft space won’t become excessively hot in summer or cold in winter.
One important point to remember with a warm loft solution is the need for ventilation immediately below the roof tiles. This prevents condensation build up or water getting in through or around the tiles, which could cause the roof structure to rot.
The more insulation we incorporate into new builds, the less energy will be required going forward.
80% of heat is lost through roof spaces
Is it that much?
Surely it depends on the property?
Modern insulation is much more efficient than that of even a few years ago.
Why aren’t new builds built with recycling & environmental policies as a priority?
Cost & profit margins. It’s not a priority for construction companies.
They only do the minimum required and nothing more, except on the very specialist top end builds which are few and far apart.
Would be interesting to see the potential gains available before passing judgement? Maybe it’s just not worth the capital investment?
Solar power should be integrated into every new property by law
What a novel idea?
New houses are built based on cost, not on optimum specification. If they were all built with the latest energy harvesting and saving tech we would make a massive impact on energy consumption.
By the time all cars are electric there just won’t be enough power to go round. At that point in time, someone will realise the error in not optimising new homes now.
Or building more power stations before it’s too late.
Governments have a lot to answer for
Don’t they just! Repeated administrations have failed to address the issues
You can get a grant to retrofit, but not to new build?? Crazy
Very crazy
Insulation of loft space is much harder with living spaces in the eves due to the limitations of depth of insulation materials available.
There are always limitations
Building regs always lag a long way behind actual requirements.
Always have, always will!
Nothing changes
Environmental considerations will always play second fiddle to commercial restraints
What people want and what Government think they want are two different things
Haha, that’s about the sum of it
There is no point installing quality insulation in roof spaces if the roof then isn’t maintained
A stitch in time saves at least nine
True Dat!
Or Ten?
Rock Wool is king
There is a growing list of good alternatives
Builders will always build to minimum spec if they are allowed to.
As long as new properties get bought as fast as they are finished, there is no incentive to build to a higher specification.
Force them
Demand and time constrains mean that new houses will always drag behind supply, so why bother adding value that buyers aren’t demanding?
They are always allowed to?
They have always been allowed to!
Low cost building with high margin sales prices…. aren’t we lucky!
The margins in construction are massive so there is no excuse for Government not to insist upon the integration of latest technology in every new build.
Yes
Big builders flit between profit and loss so rapidly, the government just needs to get it’s timing right, introducing new requirements so they are affordable. It would also drive tech costs down faster.
Builders often plead poverty despite posting massive profits.
Builders don’t care how much it costs to heat a house once its sold
Perhaps we should make them care? Until they do, we will get nowhere.
What’s the difference between paying £300,000 for a new house or paying £310,000? Very little, but the long term benefits would be massive
New properties could be much better built than they are. They could have rainwater recycling, roofs made of integrated solar panels and ground source heat pumps
Wouldn’t that be refreshing?
It can be done, but it’s not commercial for builders to do it
If you neglect your roof, even on a new build then it scan soon become very expensive
All you need to do it to inspect your roof once a year, and after any bad weather. It’s not that complicated
They do care, just about profits, rather than our countries and planets future!
No one does though, until rain is already coming in!
Too many people assume that buying a new home protects them from weather damage, but quite often it’s new builds that suffer more than older properties.
A badly ventilated roof, will soon rot if not repaired in good time & you won’t know until it’s too late.
You will never have as much insulation as you ideally want to have!
Buy the best insulation you can and it’ll pay dividends
Does anyone ever do that?
I suspect very few
If it’s installed correctly?
Not if you leave builders to do it for you!
Can you imagine what a house like that would look like?
A warm floor will warm the whole house, it’s been long overdue that regs now demand it.
Underfloor heating is very efficient, especially if it’s installed during construction rather than as a retrofit
Injected insulation works as a retrofit solution, but not the best solution for new builds
Ironic that putting in a cavity was considered a good thing, but we then decided to instantly fill it!
With such large scale construction currently happening, it would surely make sense to over engineer the new homes so that they over deliver on environmental impact?
You might think that.. I couldn’t possibly comment!
You’re confusing common sense with government decision making!!
As a country we are missing an opportunity to lead the word in construction technology
Wouldn’t it be nice if we took the steps to lead the world?
That’s too obvious?!
Missing or Missed! Like many of the other boats we collectively failed to jump on.
The final energy losses form new builds won’t be much improved over 25 year old construction, something has to change?
It’s so much cheaper to install energy saving tech during the build, and much less cost effective afterwards, so why not force the tech on new buyers?
When we are in charge it’ll all be different!
We could do better
C+ on school report me thinks
Why do we only legislate in half measures?
Watch this space, in 5 years, once millions of new homes have been built & all the EU workers have gone home, leaving them empty, we will no doubt want to re-spec all these properties and it’ll cost twice as much as it would have done!
If you have to ask?