Between the floors!

Have you ever thought about what is between your floors when you are doing building work? They are very important spaces so here is some wisdom:

1. Do not leave wood shavings in the gaps when you drill joists and floorboards, think how well that would go up in flames if you had a fire or electrical fault! Vacuum is your friend.


2. If you drill significant holes into a plaster ceiling, you have compromised its fire stopping ability and the building regs say you need to mitigate this. If you drill downlighters into the ceiling, either you must use the closed back ones which block fire (and cost more!) or put in a false ceiling to drill into or use a fire blocking device above the downlighter to prevent any compromise of the ceiling due to a fire.


3. If you can, fill the spaces with 'rockwool' type insulation which helps keep noises to a minimum, provides heat insulation so that warmer rooms are not heating up cooler rooms unintentionally and also it reduces the effects of drafts on potential fires - floor voids are wonderful places for fires because there are often drafts from leaky brickwork which if left un checked would feed a fire.


4. Make sure you know what you are allowed to do when notching or drilling joists for pipe and cables. You are not allowed to drill too large or too close together so find out from the building regulations guidelines. You do not want a joist to give way, especially one under a water tank, wall or bath which would go very quickly.


5. If you are pulling in cables or flexible pipes, invest in some fibre-glass pull rods. You can pull through voids that are perhaps 20 feet or more long without having to pull up any floorboards in the process.


6. If you drill outside from a floor void, close the gap afterwards with fire-rated expanding foam both to reduce chills from drafts, prevent vermin getting in and also reduce the effects of fire.


7. Watch out for noggins. They are (usually) blocks of wood which cross the void in an X shape and are to stop the joists twisting under load and over time. They can be a pain when pulling cables and pipes through. If you can raise an odd floorboard, do it near the noggins. Try and consider avoiding airlocks as well by passing water pipes under the noggins rather than over them (like I did!)