What sealant should I use on spiral duct joints?

Apply duct sealant (a non-setting mastic) to the male spigot before inserting it into the female duct end. Then seal the external joint with aluminium foil tape for maximum airtightness. For DW/144 Class C airtightness, both internal sealant and external tape are recommended.

How far apart should duct supports be?

Horizontal duct runs should be supported at maximum 2-metre intervals. Vertical runs require support at each joint and at 2-3 metre intervals between joints. Heavier ducts (larger diameters or those carrying heavy components) may need closer support spacing.

What size threaded rod do I need for duct suspension?

M8 threaded rod is suitable for most small to medium duct sizes (up to about 400mm diameter). M10 or M12 is recommended for larger ducts and heavier loads. Always calculate the load (duct weight plus contents) and check the rod capacity, including a safety factor.

Fasteners, Fixings and Accessories

Everything needed to hang, join, seal and finish a ductwork installation — in one place, from a Leicester-based UK ventilation supplier. This range covers the consumables and fixings that installers actually use day to day: threaded rod and slotted channel, duct suspension clips, screws, sealants, tapes, lagging and wire rope suspension systems. Stocked items ordered by 3pm are despatched for next-day delivery.

Suspending and supporting ductwork

Threaded rod and fittings — M8 and M10 rod in 3m lengths, with connectors, cap ends, beam clamps, purlin clips and eye bolts.
Slotted channel and fittings — 41mm x 21mm and 41mm x 41mm channel in 3m lengths, light and heavy gauge, plus 45 and 90 degree connectors, flat plates, channel nuts and cap ends.
Duct clips — split rings from 80mm to 1000mm and suspension rings from 80mm to 400mm, matching every spiral duct diameter we sell.
Wire rope and fixings — 2mm wire rope on 100m rolls with wire clutchers for fast, adjustable suspension.
Flexi-feet with strut, from 250mm to 1000mm long, for supporting duct and plant at roof level.

Joining and sealing ductwork

Screws — self-drilling tek screws in trade boxes of 1,000, complete with drill bit.
Sealants — duct sealant for airtight joints on spiral and rectangular systems.
Tapes — foil duct tape in 50mm and 100mm widths plus gasket tape for flanged joints.
Nuts, bolts and washers — hex head set screws, full nuts, wedge nuts, channel nuts and penny washers in M8 and M10, supplied in boxes of 100.
Lightning band on 30m coils with band housings for fast duct jointing and suspension.

Insulation and cutting

Insulating duct wrap comes in 18m rolls for thermal and condensation control on metal duct runs, and cutting discs keep site work moving on installation day.

Why order fixings with your ductwork?

Nothing stalls an installation like running out of the small stuff. A typical spiral duct project needs a support point roughly every few metres — that means split rings, threaded rod, channel or wire rope, plus the nuts, washers and screws to pull it all together — and every joint needs sealing if the system is to hit its airtightness target. Because our duct clips are sized to the same 24 diameters as our ducting and fittings, you can add matching supports to the same basket line by line: 224mm duct, 224mm split rings, rod, channel and sealant, all in one delivery with nothing forgotten. Trade-friendly pack sizes — boxes of 100 fixings, 1,000 tek screws, 100m wire rope rolls and 30m band coils — keep the van stocked for the whole job. UK mainland delivery is free on orders over £400 ex VAT.