Hi Joe 90 and James

My recommendation would be to commission the services of one of Excel's approved installers. They will fill the pitched roof void by using a 'lance or hose withdrawal method'. We are about to launch a new BBA certificate, which covers using Warmcel in this application.

In terms of the Warmcel thermal conductivity curve, the thermal conductivity does not start to increase until the density rises above 75kg/m3, which is a higher density than the product's normal installation range.

If you contact Excel's Sales office they will put you in contact with some BBA approved Warmcel installers in your area - the list is also on our website (www.Excelfibre.com).

Hi Viking House

Many thanks for your synopsis. The high level of thermal mass/decrement factor associated with Warmcel explains its widespread use in colder countries (Scotland/Scandinavia/Central Europe/Canada/colder parts of the USA), which have long and cold winters.

Hi Neil

What is the build-up of the 55dB wall? Is that de-coupled studs with double plasterboard?
What dB would you expect for a 200mm floor insulated with Cellulose?
The joists we use in the floors are the open ones with the steel zig zag webbing and sometimes I beams in the floors.
What density of Cellulose do you recomment for internal floors?

Joe90

Not being pedantic, but what you stated as your roof construction is actually a cold roof!

Viking house

The acoustic performance would also depend on spec of deck and ceiling. For instance, 22 mm t&g chipboard above and 15 mm plasterboard below would give an Rw of 40dB with mineral fibre insulation. With something dense like warmcel, I would expect an Rw of around the 45 dB mark.

Onsite this would drop to something like a DnT,w of 35 - 40 dB depending on a few other aspects.

The specs of TF party walls are usually two leaves of 89 mm studwork separated by a 50 mm cavity. Wall linings would be one layer of 19 mm plasterboard plank and one layer of 12.5 mm plasterboard. Usually both leaves are filled with 50 mm plus glasswool insulation.

55 dB DnT,w + Ctr (which is what neil is stating) is achieveable with mineral wool, but again the added density of warmcel will help improve the performance a little. The insulation within the wall, however, is not the be all and end all, good plasterboard spec is also very important.

Timber