What spacing should resilient bars be at?

Resilient bars should typically be fixed at 400mm centres for ceilings and 600mm centres for walls. 400mm centres give better acoustic performance and support heavier board configurations. Always check the specific product installation guide — some bars like Gypframe RB1 are designed for 400mm centres maximum on ceilings.

How much sound improvement do resilient bars give?

A single layer of 15mm plasterboard on resilient bar over a standard masonry or stud wall typically improves airborne sound insulation by 5-8 dB. Double-boarding (two layers of 15mm) on resilient bar can achieve 8-12 dB improvement. The exact gain depends on the existing wall construction, the quality of installation and whether all flanking paths are addressed.

Can I use resilient bars on ceilings?

Yes, resilient bars are widely used on ceilings to reduce impact and airborne sound transmission from the floor above. They are screwed to the joists at 400mm centres, and plasterboard is then screwed to the bars (not the joists). This decouples the ceiling from the structure. Combined with mineral wool insulation between joists, this is one of the most effective ceiling acoustic treatments.

What screws do I use with resilient bars?

Use 25mm drywall screws to fix the resilient bar to timber studs or joists. Fix plasterboard to the bar using 32mm drywall screws for single boards or 42mm for double boards. Critical: board screws must only go into the bar, never into the studs or joists behind, as this would create a rigid bridge and destroy the acoustic decoupling.

Do resilient bars work on party walls?

Yes, resilient bars are commonly used on party walls to improve sound insulation. For a masonry party wall, a system of resilient bar + 2 × 15mm board + mineral wool can achieve Rw 55-60 dB, meeting or exceeding Part E requirements of 45 dB DnT,w for new-build (43 dB for conversions). The key is to ensure no rigid connections between the new lining and the party wall except through the resilient bars.

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Resilient Bar Calculator — Bars, Screws & Acoustic Gain

Calculate resilient bars, screws and estimated acoustic improvement for sound-isolating wall and ceiling systems.

Wall/Ceiling Length

Total length of wall or ceiling

Wall/Ceiling Height

Height (wall) or width (ceiling)

Bar Centres400mm for ceilings, 600mm for walls

Board ConfigurationDouble-board gives better acoustic performance

Bar Price (optional)

Per 3m resilient bar

Screw Price (optional)

Per individual screw

How We Calculate This

This calculator determines the number of resilient bars, screws and estimated acoustic improvement for a sound-isolating wall or ceiling system.

The formula

Rows = Wall height ÷ Bar centres + 1

Total bar length = Rows × Wall length

For a 3.0m × 2.4m wall at 400mm centres: rows = 2400 ÷ 400 + 1 = 7. Total bar = 7 × 3.0 = 21.0m = 7 × 3m bars.

Acoustic improvement

Single 15mm on bar: ~5 dB improvement
Double 15mm on bar: ~10 dB improvement
Single 19mm plank on bar: ~7 dB improvement

Actual performance depends on the base wall/ceiling construction, mineral wool infill and sealing of flanking paths. Based on Robust Details and manufacturer test data from British Gypsum and Knauf.