Before the insulation or solar installer arrives: a ceiling-space check

Most home-energy upgrades start in the same place: the ceiling space. Insulation installers work there, solar installers run cables and check rafters there, and electricians thread new circuits through it. Yet many people have never looked into their own roof void.

A quick look before anyone is booked helps you get accurate quotes, spot problems that need fixing first, and avoid paying for a visit that ends with "we can't start until that's sorted". It should be a look, not a job. Stay on the framing, don't touch wiring, and if anything looks wrong, stop and call the right professional.

Getting in safely

• Use a stable ladder and have someone at home while you're up there.
• Step only on ceiling joists or a board laid across them. The ceiling lining between joists will not hold your weight.
• Wear long sleeves, gloves and a dust mask. Old insulation and dust are irritants.
• Take a good torch, and on a hot summer afternoon, don't stay long: roof spaces get extremely hot.
• Don't touch any wiring. Look only.

1. Wiring

Old or damaged cabling is the first thing to look for, because it affects everyone who will work in the space after you. Warning signs include:

• rubber- or fabric-covered cables, typical of much older installations, especially if they look cracked or brittle;
• cables that have been chewed, crushed or have exposed copper;
• joins that are just twisted and taped rather than in a proper junction box;
• scorch marks around fittings or junction boxes.

If you see any of these, get a licensed electrician to inspect before insulation goes down over the top. WorkSafe's electricity pages explain what electrical work must be done by licensed workers, and it is most of it.

2. Downlights

Recessed downlights are a common reason insulation jobs stall. Older halogen downlights run hot and need clearance around them, which leaves holes in the insulation blanket and lets heat escape. Modern LED fittings rated for contact with insulation can be covered, which is better for both safety and efficiency.

Count your downlights and note what type they look like. Your insulation installer will want to know, and replacing older fittings is a job for an electrician, ideally before the insulation goes in.

3. Moisture and leaks

Insulation and water do not mix. Look for:

• stains on the underside of the roof or on the timber;
• damp or compressed patches in existing insulation;
• daylight showing through around flashings, chimneys or roof penetrations;
• mould on the framing or the back of the ceiling lining.

A leak needs fixing before new insulation or solar fixings go in. Solar mounts fix through the roof, so the installer will also want to know the roof itself is in good condition.

4. Existing insulation

Note what is already there and roughly how thick it is. Old insulation may be thin, patchy, compressed by storage or pushed aside by previous trades. If you rent your home out, the healthy homes insulation standard sets minimum levels. Gen Less explains what good ceiling insulation looks like.

If you see loose, grey, fluffy material that you can't identify, or anything that might be old asbestos-containing material around flues or as a ceiling product, do not disturb it. Get it identified by a professional.

5. Old timber

While you're looking at the framing, check for signs of the common house borer: small round exit holes in the timber and little piles of fine powdery dust beneath them. Older untreated timber is most at risk. A few old holes may be long inactive, but fresh dust or soft, crumbly timber is worth getting a professional to look at, especially before a solar installer fixes mounting brackets into rafters.

6. Wasps and other visitors

In late summer, roof spaces can hold an unpleasant surprise. Introduced German and common wasps sometimes build nests in roof voids and wall cavities, and nests are at their busiest towards the end of summer. The Department of Conservation describes these wasps as a significant pest; nests are typically about the size of a soccer ball but can grow much larger, and stings can cause serious allergic reactions in some people.

If you hear a steady humming, see wasps going in and out of a gap under the eaves or roofing, or spot a papery grey or brown nest:

• back away quietly and close the ceiling hatch;
• don't try to remove or spray the nest from inside the roof space, where you are confined, on a ladder and close to the nest;
• call a pest controller to treat it, and let any booked tradies know so they don't walk into it.

Rodent droppings, chewed insulation or nesting material are also worth noting. Rats and mice chew cables, which brings us back to point 1. If you have been hearing scratching at night, this guide to noises in the ceiling helps tell rats and mice from possums or birds.

What to tell your installer

Before a quote visit, it helps to note down:

• roughly how much headroom there is and where the hatch is;
• the number and type of downlights;
• any wiring concerns you saw;
• signs of leaks, mould, borer, wasps or rodents;
• the type and depth of any existing insulation.

Photos help too. A good installer will do their own inspection, but arriving informed means fewer surprises and a more accurate price.

Order of work

If your check turns up problems, the usual order is:

1. Pest problems (wasps, rodents) treated.
2. Leaks repaired.
3. Electrical issues fixed and downlights replaced by a licensed electrician.
4. Insulation installed.
5. Solar or other roof-mounted equipment fitted.

It is less exciting than a new array on the roof, but getting the ceiling space right first makes everything that follows safer and more effective.