Insulated vs single-skin roller door laths

Quick answer

Single-skin laths are roll-formed from one layer of aluminium, so they are light and lower in cost but give little insulation. Insulated laths are double-skinned aluminium filled with polyurethane foam, which cuts draughts, noise and condensation. Insulated laths are worth it for integral garages and garages used as rooms, while single-skin is fine for a detached garage used for a car or storage.

What is the difference between insulated and single-skin laths?

A single-skin lath is a single roll-formed strip of aluminium, while an insulated lath is two aluminium skins with polyurethane foam injected between them.

Both kinds link together to make the curtain that coils onto the barrel in the roller box. Single-skin laths are thin and light, which makes them a good match for spring-assisted manual doors and keeps the price down. Insulated laths are thicker and heavier, and the foam core makes the curtain more rigid and much better at stopping cold air and sound. In our price list, insulated doors come with a motor.

Insulated laths reduce heat loss through the door, but the garage door is still not part of your home's insulated envelope. We don't quote U-values for roller doors, because what you feel depends on the whole garage, not only the door.

What do 55 mm and 77 mm lath sizes mean?

The 55 mm and 77 mm figures are the approximate height of each lath, and larger laths suit wider doors because they are stiffer.

55 mm laths make a slimmer coil, so the roller box can be smaller. They suit single and wide single openings, and a smaller box helps where there's little room above the opening.
77 mm laths are deeper and more rigid, so they resist flexing across a wide opening and in wind. They make a larger coil, so the box is bigger.

Box sizes vary with the door height and the lath size, roughly 205 to 300 mm or more for domestic doors. At the survey we check the room you have and recommend a lath that suits the width. If headroom is tight, our low-headroom options are worth a look.

Do insulated laths make a garage warmer and quieter?

Yes, insulated laths make a garage noticeably less draughty and quieter than single-skin laths, although they won't turn it into a heated room.

Draughts and warmth. The foam core slows heat passing through the door, and a stiffer curtain sits more evenly in the guides and on its bottom seal. The garage feels less cold and draughty on winter days than it would behind a single-skin door.

Noise. Thin metal can drum in wind and rain and rattle as it moves. Foam-filled laths damp much of this, which helps if there's a bedroom above or beside the garage.

Condensation. On a cold night a single-skin door gets as cold as the air outside, so moisture in the garage can condense on its inner face and drip onto the floor. The foam keeps the inner skin warmer, which reduces this. Good ventilation still matters if you store anything that dislikes damp.

Are insulated laths worth it for an integral garage?

For an integral garage, insulated laths are usually worth the extra cost, because the garage shares walls, and often a ceiling, with rooms you heat.

A cold, draughty garage pulls warmth from the rooms beside and above it, and noise from the door carries into the house. Insulated laths help with both. They also help if you use the garage as a gym, a workshop or a utility space, or if the internal door to the house is opened often. Our page on integral garages covers the other things to think about, such as where the roller box sits and where the power comes from.

How much more does an insulated roller door cost?

An insulated electric roller door costs more than a single-skin electric door of the same width, and the gap generally grows as the opening gets wider.

Opening width	Electric single-skin	Insulated electric
Single, up to 2.4 m	£1,195–£1,745 inc VAT	£1,495–£2,295 inc VAT
Wide single, 2.4 to 3.0 m	£1,395–£2,045 inc VAT	£1,795–£2,795 inc VAT
Double, 3.0 to 4.0 m	£1,795–£2,595 inc VAT	£2,195–£3,295 inc VAT
Wide double, 4.0 to 5.5 m	£2,195–£3,195 inc VAT	£2,595–£3,995 inc VAT

Both include supply, fitting, commissioning and taking away your old roller or up-and-over door. The full list is on our prices page.

When is a single-skin roller door perfectly fine?

A single-skin door is perfectly fine for a detached garage that's used to park a car or store tools, garden equipment and bikes.

If nobody spends time in the garage and it doesn't share a wall with your living space, the extra warmth and quiet of insulated laths may not be worth paying for. Single-skin laths also keep a manual door light enough to lift comfortably, which is why our manual doors use them. They suit garage courts and lock-ups too, where cost per door matters and the garages are used for storage.

Think about insulated laths instead if the garage is integral, has a room above it, is used as a workspace, or holds things that suffer from cold and damp.

Questions

Are insulated roller garage doors heavier?

Yes. The second aluminium skin and the foam core make each lath heavier than a single-skin lath of the same size. That's one reason insulated doors in our price list come with a tubular motor, which is sized to the weight of the curtain. It also explains why manual spring-assisted doors normally use single-skin laths, which keep the curtain light enough to lift by hand.

Will an insulated roller door stop condensation completely?

It reduces it but can't promise to stop it. Condensation forms when warm, moist air meets a cold surface. The foam keeps the inner skin of an insulated lath warmer than a single-skin lath, so less moisture forms on the door. Damp cars, washing machines, tumble dryers and poor ventilation in the garage can still cause condensation elsewhere, so air flow matters too.

Can I upgrade my existing single-skin door to insulated laths?

Not usually as a straight swap. Insulated laths are thicker and heavier, so they make a larger coil that may not fit the existing box, and they need a barrel, springs or motor suited to the extra weight. In most cases the sensible route is a new insulated door. We'll look at your existing door at the free survey and tell you plainly what's possible.