6 Scary DIY Tasks You Can Do

Which "scary" DIY jobs can you actually do yourself, and what do you need for each?

Six jobs that most people assume need a tradie are genuinely within reach of a competent beginner: mounting bathroom accessories on tiles, replacing perished silicone, re-fixing a loose pool tile, patching a large hole in plasterboard, repairing a chipped tile, and sealing a leaking gutter. None of them needs a licence, and only one needs power tools. What they do need is the right product and enough patience to let it cure.

The single thing that decides whether these jobs succeed is cure time. Almost every failure in this list comes from putting the repair back into service before the adhesive or sealant has reached strength. Each job below gives the published figure from the product's technical data sheet, so you know exactly how long to leave it alone.

1. Installing bathroom accessories onto tiles

You need Selleys Hold Up, the accessory itself, methylated spirits and a cloth. The accessory must have a flush back rather than an inset one, because Hold Up works by spreading between two faces that meet.

Make sure the surfaces are clean and free from grease, grit and grime, sanding back any loose or peeling surface first. Apply Hold Up to the back of the accessory, position it and press firmly against the wall so the adhesive spreads. Clean any excess immediately with methylated spirits.

Then leave it alone for at least 48 hours — longer in cooler or dry conditions. That figure is the cure time on the Hold Up technical data sheet, not a safety margin, and the sheet is explicit that the bond must not be disturbed until cured. The reason the wait is so long relative to how quickly the product feels firm is that Hold Up skins in about 45 minutes but keeps developing strength well beyond that.

Two numbers worth knowing before you hang anything heavy: Hold Up holds up to 240 kg/m² from the tube and 360 kg/m² from the 290 mL cartridge on vertical surfaces. For heavy objects, overhead work, or two non-porous faces such as glass on tile, the data sheet recommends using additional supports such as clamps during cure as a precaution. It is also adjustable for up to 15 minutes, so you have time to get a towel rail level.

For a longer walkthrough of this specific job, see how to attach bathroom accessories to tiles.

2. Replacing old silicone

Kit: eye protection and gloves, a utility knife, Selleys Sealant Remover, Selleys Rapid Mould Killer, Selleys No Mould, a caulking gun, methylated spirits, a scraper, a spatula, turps and detergent.

Ventilate the area first. Wearing gloves, slice through the old silicone and scrape away as much as you physically can. The remover works better the less material it has to get through — the technical data sheet asks you to cut the old bead back to a thin layer of less than 5 mm before you apply it.

Spread an even layer of Sealant Remover at least 5 mm thick over what is left. This page says to leave it for 2 hours; the current Sealant Remover data sheet gives a removal time of 10 minutes and notes that a second application is sometimes needed. Ten minutes is therefore the minimum. A longer dwell is what many people find works on stubborn residue, but the data sheet also warns not to leave the product on porous materials or acrylic-painted surfaces for extended periods, so check what you are working on before you walk away for two hours. Scrape the softened sealant off, then clean the area with methylated spirits.

Spray the joint with Rapid Mould Killer, leave 2–3 minutes, then rinse with water or wipe well with a damp cloth. Let it dry completely — a fan or an old towel helps. Silicone will not bond reliably to a damp joint, and a shower corner holds water long after it looks dry.

Apply No Mould once dry, pushing the sealant well into the joint rather than laying it on the surface, and tool it with a spatula dipped in detergent and water within 5 to 10 minutes of application. After that the surface starts to skin and tooling tears it. Clean up with turps before the product skins. No Mould's published figures are a skin time of 20 minutes and a cure rate of 2 mm per 24 hours, so a deep bead takes proportionally longer to reach full cure.

There is a fuller guide at how to replace old silicone.

3. Fixing a loose pool tile

Kit: Selleys MarineFlex, a caulking gun and a cloth. The point of this job is that you do not drain the pool — MarineFlex can be applied to wet surfaces and will cure under water.

Chip away as much of the old adhesive as possible, make sure the tile and the pool surface are clean and free of oil, grease, dirt and dust, apply MarineFlex to the back of the tile, position it and press down firmly. Remove excess with a cloth while you are still under water, before skinning occurs. The data sheet gives skin formation at approximately 40 minutes and a curing rate of about 2 mm per 24 hours, with faster curing in wet conditions and submersion.

One limitation to take seriously. The MarineFlex data sheet lists "not suitable for permanent water immersion or plugging leaks subject to pressure" among its limitations, and its 10-year watertight guarantee applies to above-the-waterline applications only. It also advises that critical seals and repairs made under water should be regularly checked and repaired if required. Re-sticking a decorative tile is not a critical seal, but treat it as a repair you inspect rather than one you forget about. MarineFlex also cannot be used on flexible vinyl pool liners, inflatable pools, or chlorinated rubber-based pool paint.

Step-by-step detail is at how to repair loose pool tiles.

4. Patching a large hole in plasterboard

Kit: Selleys Spakfilla Rapid, 240 grit sandpaper, a sanding block, a cloth, a spatula, an adhesive mesh patch and a utility knife.

Clean around the hole and use the utility knife to remove flaky or loose debris. Smooth the edges with sandpaper and wipe the dust away. Cut adhesive mesh to fit over the hole with 20–30 mm of overlap all round, peel the backing, centre it and press it firmly onto the wall.

Using the supplied spatula, press Spakfilla Rapid over the mesh in a wiping motion from opposite directions so the mesh is completely covered, and extend the filler 20–30 mm past the mesh edges to give yourself a feathered edge. Remove the excess with a single downward stroke.

Drying time depends entirely on thickness, and this is where people come unstuck. The Spakfilla Rapid data sheet gives 30 minutes for applications under 2 mm and 24 hours for anything over 2 mm. A patch over mesh is comfortably over 2 mm, so the advice to let the reapplied coat dry thoroughly — up to a day — before sanding and painting is the figure to work to, not the 30 minutes. Lightly sand, wipe away dust, reapply if the first coat has shrunk, then sand and paint.

Spakfilla Rapid is paintable with water-based paints once set; for oil-based paints the data sheet asks for 24 hours. It is not for load-bearing use and should not be nailed.

5. Repairing a chipped tile

Kit: Selleys Knead It Aqua, a utility knife, sandpaper with a block, a cloth, gloves and a flexible spatula. This works for small chips and cracks; a badly broken tile still needs replacing.

Clean the surface thoroughly — Knead It Aqua bonds better if you roughen the bond area before cleaning it. Cut off a piece no less than 1.5 cm with the utility knife. Wearing gloves, knead it until it is warm, soft and uniform in colour, and get it onto the job within about 10 minutes of mixing.

For cracks, work the product forcefully into the surface with a flexible spatula. For chips, fill the gap and mould it to fit. Remove excess with a damp cloth before it hardens, which is much easier than sanding it off later.

This page says to allow 2–3 hours before sanding to shape. The data sheet is slightly more generous: the product hardens in 20–30 minutes and can be drilled, sanded, machined, filed, sawed and painted after 60 minutes, with full cure at 24 hours. Either way, do not put the surface back into heavy service until the 24 hours is up.

6. Sealing leaking gutters

Kit: Selleys Storm Sealant, a caulking gun, mineral turpentine, a spatula and a cloth.

Storm can be applied directly to a leaking gutter and forms an instant seal, including in the rain. Clean the gutter of dirt, grease and grime, fit the cartridge into a caulking gun and apply to the joints or gaps, then smooth off with a spatula dipped in turps.

Do not disturb it until cured — approximately 48 hours. Storm's published figures are a skin time of 15–30 minutes and a cure rate of 2.5–3 mm per 24 hours at 23°C and 50% relative humidity, with a movement capability of ±20%. It is suitable for PVC and Colorbond gutters, and it is supplied in 290 mL cartridges in grey and black.

The limitations matter here. Storm is not suitable for plastics such as polyethylene and polypropylene (or PTFE), and not for plugging leaks subject to pressure — a leaking gutter is fine, a pressurised pipe is not. It cannot be painted with solvent-based paints; if you need to paint over it, use a water-based exterior paint applied in two coats after the sealant has cured.

Common questions about these six jobs

How long before I can use a towel rail I have stuck to the wall?

At least 48 hours, and longer in cool or dry conditions. That is the published cure time for Selleys Hold Up, and the bond must not be disturbed before then.

How much weight will Hold Up carry on a wall?

Up to 240 kg/m² from the tube and 360 kg/m² from the 290 mL cartridge on vertical surfaces. For heavy or overhead items, and for non-porous surfaces such as glass and metal, the data sheet recommends additional supports such as clamps during cure.

Can I put new silicone straight over the old bead?

No. Cut the old bead out, remove the residue with Sealant Remover, kill any mould and dry the joint before applying fresh silicone.

How long do I leave Sealant Remover on?

The current data sheet gives a removal time of 10 minutes, applied at least 5 mm thick over old sealant that has been cut back to less than 5 mm depth, with a second application sometimes needed. Do not leave it for extended periods on porous materials or acrylic-painted surfaces.

Do I have to drain the pool to re-stick a tile?

No. MarineFlex can be applied to wet surfaces and will cure under water. Clean the tile and the substrate of oil, grease, dirt and dust first, and wipe the excess off with a cloth before it skins.

Is MarineFlex a permanent fix under water?

Treat it as a repair to inspect. Its data sheet lists permanent water immersion among its limitations, the 10-year guarantee covers above-waterline use only, and it asks that critical underwater seals be checked regularly and repaired if required.

How long does a large plasterboard patch take to dry?

Spakfilla Rapid dries in 30 minutes at less than 2 mm and 24 hours at more than 2 mm. A patch over mesh is well over 2 mm, so allow up to a day before final sanding and painting.

Can I paint over Spakfilla Rapid straight away?

With water-based paints, once the filler has completely set and been sanded. For oil-based paints, allow 24 hours.

How soon can I sand a Knead It Aqua tile repair?

It hardens in 20–30 minutes and can be sanded, drilled or filed after 60 minutes. Full cure is 24 hours.

Can I seal a gutter while it is still raining?

Yes. Selleys Storm forms an immediate waterproof seal on wet or dry building materials and can be applied in the rain. It still needs about 48 hours undisturbed to cure.

Will Storm work on any gutter?

It suits PVC and Colorbond gutters. It is not suitable for polyethylene, polypropylene or PTFE, and not for plugging leaks subject to pressure.

Which of these jobs needs power tools?

None of them. A utility knife, a caulking gun, a spatula, a sanding block and gloves cover the whole list.