Silicone, caulk or adhesive: which sealant for which job?

Which sealant do I need for which job?

Choose by the job first and the surface second. A sealant fills and closes a joint. An adhesive holds two things together. Foam fills a void. A cleaner prepares the surface so that any of the others will stick. The table sets out each product in the catalogue.

Which product for which job

Job	Product	Inside or out	What it is
Gaps before painting	Soudal Decorators Caulk, 290ml	Inside	Acrylic, solvent free, can be painted or papered over when cured
Bath, shower, kitchen	Stay Fresh Anti-Mould Sealant, 290ml	Check the label	Contains an anti-fungicidal agent; clear or white
General silicone	Trade Multi Purpose Silicone, 270ml	Both	Acetoxy; fungicide resists mould; clear, white or brown
Flexible joints	Silirub LM, 300ml	Resistant to UV, rain and snow	Neutral cure; clear, white, black or anthracite grey
Roof and gutter joints	Trade Roof & Gutter Sealant, 290ml	Roofing and guttering	Bitumen based, black
Lead flashing	Trade Lead Sheet Sealant, 290ml	Roofing	Neutral cure, lead grey
Sealing and bonding in one	Fix All Flexi, 290ml, black	Both	MS polymer, suitable for most materials
Fixing panels and trims	Everbuild Multi Stick, 350ml	Wet or dry	MS polymer grab adhesive
Polystyrene or porous surfaces	Soudal Grip ALL, 290ml	Moisture resistant	Solvent free grab adhesive
Filling voids	Gap Filler B3, 750ml	Check the label	Hand held or gun grade

How does decorators caulk differ from silicone?

Decorators caulk is acrylic, so it takes paint and can be papered over once it has fully cured. It is solvent free and for interior jobs, around skirting boards, architraves, staircases, coving and internal window frames.

Silicone stays flexible and suits wet areas and flexible joints. Choose the silicone colour you want to finish with. If the gap will be painted, use caulk. If it will be wet, use silicone.

Which silicone for a bath, shower or kitchen?

An anti-mould silicone. Stay Fresh contains an anti-fungicidal agent and is for baths, tubs, kitchens and humid places. The Trade Multi Purpose silicone also lists baths, showers and sinks and contains a fungicide that resists mould growth. The wall panel guide uses an anti-mould silicone on the visible joint at a bath or tray, tooled to a 6mm bead, with the bath full of water while it cures so the joint stays intact when someone gets in. See how to fit PVC wall panels.

Which sealant for windows, doors and frames?

Silirub for a joint with a colour requirement, the multi purpose silicone for a general one. Silirub has high movement capability and primerless adhesion on glass, plastics, masonry, metals and wood. Silirub LM comes in black and anthracite grey as well as clear and white. Clean the frame first. Soudal PVCu Solvent Frame Cleaner removes ingrained dirt from white or veneered PVCu, and the cleaners range also has glass and mirror cleaner for the glazing.

Which adhesive for PVC panels, trims and fittings?

An MS polymer or solvent-free grab adhesive. The panel guides use these because they suit the printed face of a PVC panel. Run vertical beads at about 300mm centres, plus a bead 10mm in from the edges, and allow around one 290ml tube per 2m². Foam tape holds a ceiling panel up while the grab adhesive takes. Fix All Flexi is the one for a joint that must also be sealed. Superglue HV and its activator are for small, non-porous jobs such as rubber, metal, plastic and glass. See adhesives.

How do I get a clean joint?

Clean and dry the joint first, removing soap film, dust and damp. Use the PVCu frame cleaner on frames and the glass cleaner on glazing, and wipe the joint dry. The wall panel guide says to pack out a gap wider than about 6mm, or fit a trim, before using silicone. Cut the nozzle to the bead size you need, run one continuous bead, and tool it smooth before it skins. Leave it to cure before it gets wet. The panel guide allows 24 hours before a shower is used.

What do I use to clean up afterwards?

Swipex wipes are heavy duty wipes for sealant stains and dirt on surfaces, tools and hands, 100 to a pack. Soudal Foam & Gun Cleaner is for foam guns and uncured foam, and the glass and mirror cleaner is alcohol based and fast drying. Uncured foam and wet sealant come off far more easily than cured, so clean up before it sets.

When do I use expanding foam?

To fill holes, voids and gaps too large for a bead of sealant. Soudal Gap Filler B3 comes in a hand held can and a gun grade can, both 750ml. Gun grade goes through a foam gun, so budget for a gun and a can of foam and gun cleaner as well. Trim and cover foam once it has cured.

What about roofs and gutters?

Use the products made for them. The roof and gutter sealant is a bitumen-based sealant for guttering, downpipes, chimney stacks, lap joints and flashings. The lead sheet sealant is for sealing lead into brick, stone or concrete. Both are 290ml. For a verge or ridge on a Liteslate roof, read how do I fit continuous dry verge, as the fix there is mechanical.

Where can I get sealants in Liverpool?

Collect free from the Liverpool showroom at Unit 7, The Boxworks, Heysham Road, L30 6UR, Monday to Friday 7:30am to 4:30pm and Saturday 7:30am to 1pm. Delivery is priced by postcode and shown on each product page and at checkout. Tell us the surface and the job and we will match the product. The whole range is in sealants, adhesives and cleaners.