What it is called, by market
One concept, four markets. Where a name means something else locally, the card says so rather than leaving you to find out on site.
United Kingdom
Close, not identicalnoggin
also nogging, dwang, strutting
Dwang is Scottish and northern usage for the same piece; strutting more often names the equivalent between joists rather than between studs.
Australia
Close, not identicalnogging
also noggin, blocking
Both words in use, with nogging the more common in framing documents and blocking increasingly common under American influence.
United Statesyours
Same word, different thingblocking
also bridging, fire blocking, backing
Bridging in North American usage usually means DIAGONAL cross-bracing between joists, not a solid piece — so a British noggin translates to solid blocking, and calling it bridging names a different member.
Canada
Same word, different thingblocking
also strapping, bridging, cross-bridging
As the United States, and Canadian strapping adds a second trap — it means the light battens run across the underside of joists, not the pieces between them.
The governing standard, by market
United States
IRC R502.7 / R602.8
Lateral restraint of joists and fireblocking requirements in concealed framing spaces.
United Kingdom
BS EN 1995-1-1 / Approved Document B
Timber structure design, and cavity barriers within concealed spaces in construction.
Calculators for this
Each works in either measurement system, and the terminology on the page follows whichever market you have selected.
Frequently asked questions
- Are noggins structural, or just somewhere to screw into?
- Both, and which one governs decides where they go. As structure they stop a slender member buckling sideways or rotating under load, which is why rows appear at intervals along a long stud or across a joist span rather than wherever convenient. As a fixing they carry things a board alone will not hold — a wall-hung basin, a television bracket, a handrail, a heavy cupboard — and those go exactly where the fitting lands, which is a decision made from the layout drawing rather than from a spacing rule. A third role is neither: in some constructions the same piece acts as a cavity barrier or fireblock, and then its material and its fit to the surrounding timber are specified rather than left to the carpenter.
- Why does the American word bridging mean something different?
- Because it names the diagonal version rather than the solid one. Restraint between joists can be provided two ways: a solid piece the full depth of the joist, or a pair of diagonal members crossing between adjacent joists in an X. North American usage calls the solid one blocking and the diagonal one bridging or cross-bridging, and they are ordered, priced and installed differently — diagonal bridging is a much smaller section, cut at an angle, and much faster to fix. British usage tends to call both strutting, distinguishing solid strutting from herringbone strutting. So a drawing that says bridging is not asking for a noggin, and reading it as one changes both the material list and the labour.
- Where do noggins go if the drawing does not say?
- Three places, and only the first is a rule of thumb. First, at the height where board edges meet — plasterboard, sheathing or panelling needs a fixing along every edge, and a horizontal joint between sheets has nothing behind it unless a noggin is put there. Second, wherever a fitting will be hung, taken from the sanitaryware and joinery layouts rather than guessed, because a noggin fixed after the boards are on means cutting the boards. Third, at whatever interval the structural design requires, which for studs is commonly around mid-height on a standard wall and for joists depends on the span. If a drawing shows none at all on a long span, that is worth querying rather than assuming.