Old floorboards were natural draughty. When they were installed we didn’t have tongue and groove flooring and the boards were not always particularly straight. Time, wear and tear, moisture content changes in the home etc have all contributed their little bit towards more ill fitting boards. The floors themselves need a draught underneath to keep the walls dry. A good draught wicks away moisture from the soil below the floors and the lower portions of the walls, thus helping to keep rising damp at bay.
The following solutions will look at how to keep the existing floorboards (with all their character and charm) rather than the potential horrors of laminates and replacement concrete floors.
With energy efficiency now being a real driver we are faced with a situation where we really need to make these wooden floors fit for the low energy age. This can actually be a simple task, but as ever there are a range of different ways of achieving this. The simplest way is to just draught proof them using an expanding ‘V’ shaped plastic product. Basically this ‘V’ is pushed down into the gap to provide a seal in between the boards. This ‘V’ is initially compressed and it naturally expands out to take into account the variable width of the gap. This is a Welsh product that will be available from the Eco Home Centre soon. more info can be found at www.stopgaps.com. This solution can radically reduce draughts, but it does not insulate the floor.
To insulate and draught proof takes a little more work.
To improve the efficiency of the floors we need to get some insulation into them. This insulation should be breathable because if we use non-breathable insulation it will trap more moisture below the floor and also concentrate any moisture movement through the breathable elements (i.e. wood) and both of these will increase the chances of rot. So using breathable insulations like cellulose, sheep’s wool, hemp etc is really important. Similarly if you use any membranes then these also need to be breathable.
In its most basic form we need to put insulation between the floor joists. This can be done from below (if you have a cellar or a large void under the house), or more commonly from above (this means taking up the boards to gain access).
If working from below insulation can be wedged between the joists and then a breather membrane / netting can be stapled to the joists to keep it all in place. If using a breather membrane (this acts as a better airtightness solution) then use a good quality sealant to join the membrane to the walls at the edges to ensure that draughts are not created under the skirting boards.
If working from above then lift the boards and then you can drape the membrane / netting over and down the joists to create a base for the insulation. Again use a really good sealer around the edges of the room and also remember to tape up the strips of membrane to ensure an airtight finish. Insulation can then be added and the joists replaced.