Knowles Services Ltd
Loft insulation top-ups
Thin loft insulation brought up to at least 270mm, usually in a single day. Free survey, fixed quote, nothing to pay until it's done.
Call Dean free 0800 772 0724 8am–9pm, 7 days · speak to the installer, not a call centreOr leave your number and I'll call you back
- Free loft survey
- No upfront payment
- 10-year warranty
- Fully insured & DBS-checked
Is a top-up enough for your loft?
If your loft already has some insulation and it's in decent condition, you usually don't need to rip it out. Adding a new layer on top is quicker and cheaper.
Thin insulation lets heat escape through the roof. Topping it up is one of the simplest ways to keep your home warmer.
A top-up is usually right when the existing insulation is:
- Dry. No damp patches, staining or musty smell.
- Clean. No droppings, nests or heavy debris.
- Lying flat and even. It's just too thin, often 100mm or less, when 270mm is now recommended.
If it's damp, dirty, crumbling, or might be vermiculite, it shouldn't be covered over. See loft insulation removal and loft cleaning, or my guide to the types of loft insulation to see what you've got.
Drawings for illustration.
How I top up your loft
I survey every loft myself and I'm on every job. Most top-ups are done in a single day.
- I protect your home Dust sheets from the loft hatch to the front door, and shoe covers indoors.
- I check the loft I measure the existing insulation, check the ventilation and look for damp, damage and anything that shouldn't be disturbed.
- I seal the gaps Gaps in the ceiling around pipes and cables are sealed so warm, damp air doesn't leak into the loft.
- I lay the new insulation A new layer goes across the joists to bring the total to at least 270mm, cut neatly around pipes and fittings and kept back from the eaves so air can still move through the loft.
- I check the loft hatch And insulate and draught-proof it where it needs it, so heat doesn't escape straight through.
- You pay when it's done Nothing upfront, and a 10-year warranty on materials and workmanship.
How much does a loft insulation top-up cost?
Top-ups start from £500. Every loft is different, so I look first and then give you one fixed price.
What changes the price
- The size of your loft.
- How much insulation is already there, and how much needs adding to reach 270mm.
- Access: the size of the hatch, and how easy it is to move around the loft.
- Boarding: if you want raised boarding on legs for storage.
- Anything that needs sorting first, such as damp, droppings or old insulation that has to come out.
The survey is free and there's no obligation. You get the price in writing and decide in your own time.
See my work
Real jobs, with photos and video from start to finish.
What my customers say
“It's hard to find tradesmen you can trust, but Dean was honest and straightforward from start to finish. The loft work was done to a high standard, and he went above and beyond! Thank you Dean!”
“Very pleased with the work Knowles Services did on my loft. Dean explained everything clearly, turned up when he said he would and left the place clean.”
Questions about loft insulation top-ups
How much does a loft insulation top-up cost?
Top-ups start from £500. The price depends on the size of your loft, how much insulation is already there and how easy the loft is to get into. After a free survey you get one fixed price, and you pay nothing until the job is done.
Can new insulation go on top of the old?
Yes, as long as the old insulation is dry, clean and lying flat. If it's damp or dirty, it needs clearing out first. If it might be vermiculite, I won't disturb it: some contains asbestos, so it needs testing first.
How long does a top-up take?
Most top-ups are done in a single day.
Can I still store things in my loft?
Yes. Raised boarding on legs keeps your storage space without squashing the new insulation.
How deep should my loft insulation be?
At least 270mm of mineral wool is the current recommendation. Many older lofts have 100mm or less.
Book your free loft survey
Call 8am–9pm, 7 days a week, or send the form and I'll call you back.