GRPSectional TIF Tanks

TIF stands for Totally Internally Flanged, meaning every panel joint — base, sides and roof — is bolted from inside the tank rather than externally. This makes them ideal where space around the tank is tight, as no external access is needed for assembly or future maintenance. The trade-off is that they must sit on a flat, level, continuous foundation, typically a concrete slab, rather than a supporting steel grillage.

Because the base is internally flanged and unsupported from below by a frame, TIF tanks need a flat, level and continuous foundation capable of bearing the full water load evenly across the base. A structural concrete slab, designed by your engineer for the tank's filled weight, is the standard solution. Uneven or point-loaded support can distort the panels and compromise the joints, so this isn't an area to cut corners on.

Our standard TIF range runs from 1,520 litres up to 12,733 litres, built up from modular GRP panels. Because the tanks are sectional, we can configure panel combinations to suit specific footprints or headroom restrictions, not just off-the-shelf capacities. Get in touch with your dimensions and required volume and we'll advise on the best makeup.

Yes, TIF tanks can be supplied in specifications suitable for wholesome (potable) water storage, built to WRAS-approved materials and standards. They're equally available in non-potable builds for grey water, rainwater harvesting or industrial process water. Make sure you specify the intended use when ordering, as fittings, liners and jointing compounds differ between potable and non-potable builds.

Standard TIF tanks are supplied with insulated side panels and roof as part of the build, which helps protect stored water from freezing and temperature swings in an external, above-ground installation. This is generally adequate for most UK sites, though very exposed locations or particularly cold-sensitive applications may warrant additional cladding or lagging. Speak to us if your site has unusual exposure and we can advise on extra protection.

TIF tanks arrive as flat-packed GRP panels along with all fixings, gaskets and internal flange bolts, rather than as one pre-assembled unit, which keeps transport and access straightforward even on restricted sites. Assembly is done in-situ directly on the prepared concrete base, with all bolting carried out from inside the tank. Lead times depend on tank size and current stock, so it's worth confirming build schedules with us before finalising your groundworks programme.