Loft insulation · Bristol
Loft insulation, laid to depth and left that way
Most lofts we open are insulated to a standard that was current decades ago, then partly flattened by whatever has been stored on top of it.
- Topped up to current recommended depth
- Laid across the joists so there is no cold bridge along every timber
- Fitted around raised boarding rather than squashed under it
- Eaves ventilation kept clear, so the loft still breathes
5 years · 500+ installs · 4.9/5 · Fully insured
Typical three-bed semi
From £500
Laid to around 270mm
Depth is everything
Thin insulation is not half as good — it is far worse than half
Insulation works by holding still air. Depth is what holds it. A loft with 100mm of settled wool is not two-thirds as effective as one with 270mm; the loss is disproportionate, and it is worst exactly when the weather is worst.
Measure before you assume
Settled insulation looks deeper than it is. We check depth against the joist rather than by eye.
Cross-lay the top layer
Running the second layer at right angles across the joists removes the cold line along every timber.
Keep the eaves clear
A cold loft has to ventilate. Stuffing the eaves is how damp problems begin.
Insulation and boarding
The two jobs fight each other unless you plan them together
Storage and insulation want the same space. Boards laid on the joists win that argument by flattening the wool. Raised boarding lets both have what they need.
- Insulation to full depth first
- Raised boarding built above it, never on it
- A ventilation gap kept between the two
- Both jobs done in one visit, one set-up
Don't forget the hatch
A perfect loft with a leaking lid
There is little point insulating 40 square metres of ceiling and leaving a square metre of bare, unsealed board in the middle of it. The hatch is a direct opening between a heated landing and a cold loft, and it is usually the cheapest part of the job to fix.
Insulated hatchesCommon questions
Questions about insulation
How deep should loft insulation be?
Current guidance for a cold loft is commonly cited at around 270mm of mineral wool. A great many Bristol lofts have well under half of that, often laid decades ago and never topped up.
Can you insulate and board at the same time?
Yes, and it is the right order to do it in. Insulation goes to full depth first, then raised boarding is built above it so nothing gets compressed. Doing them separately usually means undoing the first job.
Do I need to remove the old insulation?
Usually not. Existing insulation that is dry and in reasonable condition can be topped up by laying a second layer across the joists at right angles. We only take insulation out if it is wet, contaminated or degraded.
Should insulation go under the eaves?
It should stop short of blocking the ventilation path at the eaves. A cold loft needs to breathe; sealing the eaves is how condensation problems start.
Are there grants available?
You may qualify for help with the cost, depending on the property, the household and whichever scheme is running at the time. It is worth checking the Great British Insulation Scheme and the wider government energy-efficiency pages, both linked below. We cannot promise funding and will not pretend otherwise — the schemes and their criteria change.
Useful guidance
Official sources, if you want to check any of this
We would rather you verified the standards than took our word for them.
- Energy Saving Trust — independent advice on depth, savings and payback
- Approved Document L — the official energy standard behind the 270mm figure
- Great British Insulation Scheme — check whether you qualify for help with the cost
- Find energy grants — other official schemes worth checking
Ready to get started?
Find out what your loft actually has
We will measure the depth you have now before recommending anything. Call 0117 463 6501.
- 5 years
- 500+ jobs
- 4.9/5
- £5m insured
- 12-month workmanship guarantee