There is a common belief that wood floors are cold and noisy. This idea stems from the fact that original wood floorboards in older badly insulated houses were in fact cold and draughty . However this was in the days before central heating and insulation was the norm
These days you will find that wood flooring can be warm, quiet and resilient to walk on. Hardwood floors today are far more stable. They do not shrink and gap anything like the floors of yesteryear
Engineered and solid wood flooring now comes tongued and grooved on all four sides of the board that make a surface that is impenetrable to draughts In the case of a solid wood floor laid directly onto joists, the 20mm thickness of tightly fitting solid oak will give far more insulation than pine.
The noise generated by the sound of foot traffic over a wood floor is greatly reduced by correct installation methods. The use of a sound deadening underlay will also give good benefits and make the floor far easier to live with.
The comparison between wood and laminate flooring should also be a consideration.
Laminate flooring is backed with an HDF (high density fibre board) which is a very hard and dense material that does not easily absorb noise Real hardwood flooring on the other hand more readily absorbs the tapping of footsteps. This is because wood flooring has more natural sound insulation and when installed properly the sound is minimal.
When installing an engineered board the standard installation method is to float the floor by laying it on top of the structural sub-floor. This makes a void between the two floors so it needs something in between to soak up the noise. This is where the underlay is used. The underlays range from a basic 1.5mm foam which can soak up.
Higher up the scale are the high-density sound deadening wood floor underlays which have been proven to give high acoustic properties and Keep the noise down to an acceptable level. These underlays can reduce the sound going through the floor down to 22db, which is extremely good. Generally the price dictates the quality of the underlay and the more expensive, the higher specification.
Remember, the better underlays reduce noise levels the most. However always use an underlay that is specifically made for wood flooring. Carpet underlay for instance will be too springy for wood flooring, making the joints weaken
Wood Floor Underlay Types
Underlay Boards
These are usually about 1.20m x 0.80m and are loose laid over the floor with staggered joints in the opposite direction to the intended direction of the new wood flooring. Try to avoid the fibreboards that are made from recycled cardboard and paper. Although cheap to buy, these tend to be extremely absorbent, so a small amount of moisture will soon cause a big problem. The polystyrene or closed cell polypropylene boards such as Depron or Strata will provide better leveling, thermal and sound reducing properties as well as being waterproof.
Sound Deadening Underlay
These are between 4mm and 6mm thickness in a roll width of about 1.20m, these underlays will be extremely effective at reducing the amount of noise that travels through the floor and these are therefore the best type to use if you are installing in an apartment building.
Cush-n-Wood made by Ball & Young is a good high specification product that is relatively inexpensive. Also look at Unisound underlay, or Transit Sound underlay manufactured by Unilin who make the Quick-Step ‘Uniclic’ laminate flooring.
Synthetic Foam Underlays
These are relatively cost effective to buy and fast to fit. They provide limited leveling properties and they are therefore ineffective at reducing noise over an uneven floor. They are usually available in rolls of 15 sq mtrs – 11.5m x 1.2m or 15m x 1m
If used in conjunction with an underlay board, they are effective in reducing sound bouncing up from the floor. Good makes to look for are Barrier Plus, Treadmate, Alevoit
Adhesive Underlay
These can be effective on a good flat sub-floor although are a little harder to install. They are loose laid over the floor. The wood then adheres to the sticky upper side of the underlay. This can be a good method of installing a solid wood floor in apartment building. This is because no nails are used which can transfer the noise through the sub-floor. The most widely available types of adhesive underlays are Elastion, Envoy, Alustrong
To summarise, for the best sound deadening underlay for a floating floor, get an underlay that is rated 20db or higher.
For the best insulating underlay for a floating floor, try and get a thermal resistance of 0.073m2 K/W, or higher.