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Insulating Floors with Pavatex Wood Fibre Insulation

Insulating Floors With Pavatex Wood Fibre Insulation

Pavaflex Wood Fibre
A flexible and breathable wood fibre batt for snugly insulating floors between timber joists, as well as between rafters and studs to provide excellent thermal insulation results.
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Pavatherm Wood Fibre Board
A universal rigid wood fibre board for insulating internally above floor sub-decks, below roof rafters or flush with walls to reduce thermal bridging.
(Similar to Hofatex Therm)
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A high compression resistant board suitable for insulating floors above and below wet and dry screeds and above timber floor sub-decks. It significantly reduces impact sound.
(Similar to Hofatex Strongboard)
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Softboard Standard Natural Board
Softboard Standard Natural
A thin universal standard board for insulating internally above floor sub-decks, below roof rafters or flush with walls to reduce thermal bridging.
(Similar to Hofatex Standard Natur)
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Pavastep Underlay Board
A thin underlay board to reduce impact sound through timber, concrete and screed floors. Very high compression strength for insulating floors.
(Similar to Hofatex Silent)
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Insulating Floors – Between the Joists of New Timber Floors

Insulating a new timber floor is best done by filling the cavity between the floor joists with the flexible and hygroscopic insulation batt, Pavaflex. It comes in pre-cut batts at 375 and 575 mm widths and it is very easy and quick to install and does not require any protective clothing. It is very dense too at 40 kg/m³ so helps to reduce airborne noise through the floor when combined with other proprietary acoustic insulation products e.g. PhoneStar, and it will reduce reverberation within the cavity. Pavatherm can also be used between the joists but must be cut precisely to size and this can be difficult to do on-site. However this is a very good option when manufacturing timber frame buildings off-site. The sub-deck is then installed above the floor joists and there are a number of Pavatex wood fibre insulation options that can be placed above the sub-deck to further enhance both thermal and acoustic insulation through the floor.


Insulating Floors – Above a Timber or Concrete Floor

Note: If laying Pavatex wood fibre above a new concrete floor it must first be covered with a damp proof membrane to prevent rising damp and if the wood fibre is to be covered with a concrete screed this must also be protected with a damp proof membrane.


Thermal and Acoustic Floor Insulation Upgrade Option

– Thick Solution up to 160 mm

Pavatherm comes in thicknesses of between 40 mm and 160 mm so when insulating floors the thermal resistance will improve as the thickness increases, if room height allows. The wood fibre can be laid floating in a brickwork formation on any sub-deck with the square edged boards butted up to each other. A perimeter strip or flanking strip must be inserted at all perimeter edges to reduce the risk of flanking sound. The wood fibre boards are then overlaid with a timber top-deck or a concrete screed but a damp proof membrane must be used to protect the wood fibre from the moisture of the screed. Pavatherm has a Compression Strength of 50 kPa so this should be adequate for most living spaces but when insulating floors with heavy loads it is highly recommended to use Pavaboard wood fibre boards as they have a very high Compression Strength of 150 kPa.


The Pavatherm and Pavaboard boards will reduce both airborne (e.g. talking, music) noise and impact (e.g. footstep, moving furniture) noise when insulating floors. It is estimated that 80 mm thick Pavatherm wood fibre board will provide about 27 decibels of airborne insulation on its own before it is added to the structure and it will reduce impact sound by about 28 decibels on a concrete floor with a concrete screed top-deck. Pavatherm and Pavaboard will also reduce the irritating noise of hard soled shoes clicking on hard floor surfaces.


Thermal bridging through the timber joists will be eliminated when insulating floors with wood fibre softboards and because of its density, it adds thermal mass to the structure and will store heat during the warmer times of the day and release it as the temperature drops. The wood fibre can also be used with underfloor heating. Pavatex wood fibre thermal insulation is made entirely from natural materials and so will not emit any toxic chemicals into the building and the timber is sourced from sustainably managed FSC and PEFC certified forests, so it is a very sustainable building material.


Thermal and Acoustic Floor Insulation Upgrade Option

– Thin Solutions up to 19 mm

Softboard Natural Standard is available in thicknesses up to 19 mm so is a good option to consider when the floor level cannot be raised too much. Its high compression strength (130 kPa) means it is ideal for heavy loads and the boards come in big sheet sizes so they are very quick to lay. Again they are laid floating on top of a timber or concrete sub-deck and a flanking strip must be used at the perimeter edges. If used above a new concrete floor or under a concrete screed the wood fibre must be protected with a damp proof membrane.


Softboard Natural Standard will reduce impact noise and airborne noise quite considerably. It is estimated that 19 mm thick Softboard Natural Standard wood fibre board will provide about 25 decibels of airborne insulation on its own before it is added to the structure and it will reduce impact sound by about 24 decibels when installed on a concrete floor with a 50 mm concrete screed over it. Thermal bridging through the joists will be reduced when insulating floors with Softboard Natural Standard and it will provide a warm and comfortable feeling underfoot.


Pavastep impact acoustic insulation comes in a slim 8 mm thickness and this is ideal to lay over a timber or concrete sub-deck to reduce impact noise or footstep noise through the floor. It will also reduce draughts coming up through the floor. Irritating clicking noises caused by hard soled shoes on hard floor surfaces will be reduced.  Pavastep can also be laid over Pavatherm wood fibre boards for enhanced compression and acoustic insulation results.


U-value Calculator

To calculate your own U-value figures on various structures try the Free U-Value Calculator.


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