Disposal of the old unit and the old glass

Why sealed units are awkward

A double glazed unit is not ordinary glass. It is two panes bonded to a metal or composite spacer with sealant and desiccant, and toughened or laminated on top of that.

Ordinary bottle glass recycling cannot take it. Contaminating a container glass stream with toughened or laminated glass causes real problems downstream, which is why it goes through a specialist route.

What happens to it

Units are taken to a facility that separates the components. Glass is crushed and recycled into aggregate or new flat glass, aluminium spacers are recovered as metal, and the sealant and desiccant go to appropriate disposal.

Timber frames are separated for wood recycling; aluminium frames are recovered as scrap.

Duty of care

Waste from a job is our responsibility to dispose of correctly. We hold the appropriate registration and use licensed facilities.

That matters more than it sounds. Waste fly-tipped by a contractor remains traceable to the property it came from, and householders have been pursued for it.

Old polycarbonate domes

Recyclable as plastic where facilities accept it, though yellowed and crazed polycarbonate is usually beyond reuse and goes to general disposal.

Asbestos

Occasionally relevant on older flat roofs, where some historic coverings and boards contained it. If we suspect it we stop and it is tested before anything is disturbed. That is not a job we take on ourselves.

If you want to keep it

Some people want an old cast iron conservation rooflight, and reclaimed frames have genuine value. Say so before the day and we will take it out carefully rather than efficiently.

What comes off a roof

A rooflight replacement produces more waste than people expect, and most of it is awkward.

The old sash and frame, which on a timber unit with aluminium cladding is heavy and unwieldy. The sealed glazing unit itself, which is heavy and sharp. The old flashing kit, which on an older installation is frequently lead or aluminium. Any tiles or slates broken during removal. The old internal lining where it is being replaced. And the packaging the new unit arrived in, which on a large rooflight is substantial.

On a like for like replacement that is a car boot full of material that cannot go in a household bin and will not be taken by a kerbside collection.

Why it belongs on the quotation

Disposal is one of the eight lines that should be named, and it is one of the ones most often left off a cheap price.

The consequence is not dramatic: it is a pile of glass and metal in your garden and a trip to a household waste site that will probably refuse the sealed unit as trade waste, since it arose from work carried out for payment.

It is worth asking simply so you know whether it is going with them or staying with you.

Where it actually goes

To a licensed waste facility, with the material separated rather than tipped as mixed waste.

Glass. Sealed units are not straightforward to recycle, because the two panes are bonded to a spacer with a permanent seal and the glass carries coatings. Specialist processing exists and it is not universal. What matters is that it goes to a facility that handles it rather than into a general skip.

Metal flashings. Aluminium and lead both have a scrap value and both are straightforwardly recyclable.

Timber. Frames can be processed, and treated timber has its own route.

Packaging. Cardboard and film, both recyclable and both bulky.

Lead, and being straight about it

Older rooflight installations frequently used lead flashings, and lead has a meaningful scrap value.

If we remove lead from your roof, we tell you and we account for it rather than quietly keeping it. That is not a large sum on a single rooflight and it is your material.

It is worth knowing because it occasionally explains why one quotation is lower than another: a contractor allowing for the lead value in the price is being straightforward, and one not mentioning it may not be.

What we leave rather than remove

Sound tiles or slates lifted during the work and still serviceable.

On an older covering these are worth keeping as spares, because matching a weathered handmade clay tile or a discontinued concrete profile is genuinely difficult and a small stock in the garage is worth having. We leave them stacked somewhere sensible if you want them and take them if you do not.

Anything that was reusable and is now broken goes with us.

Where asbestos may be present

Uncommon and worth mentioning, because it occurs on older flat roofs and around some mid century rooflight installations.

Asbestos cement was used for kerbs, surrounds and corrugated sheeting, and some older bituminous flat roof coverings contain it. Corrugated garage roofs are the most familiar example.

Where we suspect it, work stops and it is tested rather than guessed at. Removal is a licensed activity and it is not something we do ourselves. It is rare, it is not a reason to avoid a job, and it is one more reason we survey rather than pricing from a photograph.

Skips and permits

On a single replacement no skip is needed and the material goes with us in the van.

On a larger job, or where an extension is being built at the same time, a skip may be the sensible answer. Where one is needed we say so rather than quietly adding it, and where it has to stand on the highway it needs a permit from the council, which is a named line on the quotation rather than a surprise.

What we leave behind

The site swept, the loft tidy, and floor coverings and dust barriers removed at the end of the job rather than the following week.

Making good finished ready for decoration, unless decoration was specifically included. And the paperwork handed over on the day rather than posted later: the specification, the Building Control certificate where the work was notifiable, and the workmanship guarantee.

That last point matters more than it sounds. A job is not finished when the window is in; it is finished when the room is usable again and you have what you need to prove the work was done properly in fifteen years.

Why a sealed unit is not ordinary glass

A failed rooflight unit is two or three panes bonded to a spacer bar, with desiccant inside the spacer, a primary butyl seal and a secondary structural sealant around the perimeter. Frequently one pane is laminated, with a plastic interlayer bonded between two sheets.

That combination is why it does not go into a container of bottle glass. The metal, the polymer and the sealant all have to be separated before the glass is usable as cullet, and that separation happens at a facility set up for it rather than at a household recycling centre.

Toughened glass complicates it further. It has been heat treated, so it melts at a different rate and behaves differently in a furnace charge. Mixed into ordinary glass recycling it contaminates the batch.

The frame

Timber frames from older roof windows are frequently treated, and where they carry an aluminium cladding the two materials separate cleanly and the aluminium is genuinely valuable as scrap.

PVCu frames are recyclable through specialist streams, though the reinforcement inside them has to come out first.

Old flashing is lead or aluminium, both of which have real scrap value and should not be going to landfill.

Asbestos, and when to stop

On buildings from the relevant period, material around a roof opening may contain asbestos. Older flat roof build ups, some mid century boards, and certain bituminous products are the ones to be alert to.

Where it is suspected, work stops and the material is tested rather than removed. That is not caution for its own sake; disturbing asbestos containing material without controls is a serious matter and it is regulated accordingly.

Any competent contractor raises this at survey where the building age suggests it, rather than discovering it with a reciprocating saw.

Your duty of care

Waste from your property remains connected to you. Where it is fly tipped, the trail leads back to the address it came from, and a householder who cannot show it was passed to a licensed carrier is in a poor position.

That is why a waste transfer note matters. It is a legal document rather than a courtesy, it records who took the waste and where it went, and it is worth keeping.

Ask for it. A contractor who cannot produce one is telling you something about where the material is going.

What is worth keeping rather than removing

Sound tiles or slates that came off and were not needed. On an older roof, matching material is genuinely difficult to source, and a small stock in the garage saves an awkward compromise the next time something breaks.

The same applies to any reclaimed material sourced for the job and not used.

What should be on the quotation

Removal and disposal, as a stated line. It is not free, and where it is not mentioned you should establish whether it is included or whether you are expected to deal with a broken sealed unit and a timber frame yourself.

On a lantern or a large flat rooflight the volume is significant, and on a job where the covering is also being replaced it can be a substantial figure.

Skips, and where they can go

On a job with a covering coming off, a skip is frequently the practical answer, and its position is worth settling before the day.

A skip on the public highway needs a permit from the council, and on a narrow street in a historic centre that may not be granted at all. Permits take days rather than hours, and they carry conditions about lighting and marking.

A skip on a driveway needs no permit and needs boards under it, because a loaded skip on a block paved drive will mark it.

Where neither works, a waste carrier removing material at the end of each day is the alternative, and it should be priced rather than assumed.

Weight, which surprises people

A sealed unit is heavy. A lantern or a large walk on assembly coming out is a lifting operation rather than something two people carry down a ladder, and glass that breaks on the way down is a serious hazard.

On anything substantial the removal is planned with the same care as the installation, and it may need the same lifting equipment.

Keeping what is worth keeping

Sound tiles or slates that came off and were not needed. On an older roof matching material is genuinely difficult to source, and a small stock in the garage saves an awkward compromise next time something breaks.

The same applies to any reclaimed material bought for the job and not used.