My house is 150 years old. I'm getting the floorboards replaced and under this there are no proper foundations, just ground. Is there any way I can seal off the ground so the cold and damp doesn't come up through the floor? I wondered if there's something I can lay in between the joists, on the ground. I'm thinking that way the air can still come in the air vents and circulate under the wooden floorboards. (PS I'm planning to put laminate on top of the floor boards.). Thanks, Juls
Damp proofing under floor
- Thread starter Juls123
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your post doesn't make it clear whether there is a space below the underside of the joists, or if the joists themselves actually sit on the ground (which would admittedly be unusual).
Assuming there is a space below the joists, you need to ensure that it is well-ventilated by air bricks on opposite sides of the void. This is particularly important if it is just earth underneath. Because timber floors have to be well-ventilated, they are of necessity cold. If you are removing the floor boarding, you can put insulation boards between the joists. (4" Kingspan boards are usually installed in modern work; a few nails will hold them in position as they are very light).Your boarding and laminate can then go on in the usual way.
Assuming there is a space below the joists, you need to ensure that it is well-ventilated by air bricks on opposite sides of the void. This is particularly important if it is just earth underneath. Because timber floors have to be well-ventilated, they are of necessity cold. If you are removing the floor boarding, you can put insulation boards between the joists. (4" Kingspan boards are usually installed in modern work; a few nails will hold them in position as they are very light).Your boarding and laminate can then go on in the usual way.
Yes the joists are above the ground by about 4 or 5 inches. That's good advice thanks I'll look into getting the kingspan. Do you think it's something that I could easily install myself? All the repairs in the house are through the insurance appointed building company and they will only do like for like repairs. I know if I ask them to put this in they'll say it's private work and that they can't do it, so it leaves me with having to arrange it myself. Although I'm up for doing this and can order the materials, it's just whether you think it's a specialised job or something that can be done by a reasonably handy person.
I would value your opinion. Thanks
I would value your opinion. Thanks
This should be a straightforward DIY job.
If your joists are more than 4" deep, just hammer a few nails in the sides of the joists at a depth which will support the thickness of Kingspan you use. If they are 4" or less, you will need something like netting stapled to the sides of the joists to hold the Kingspan. The K'span is easy to cut with a saw.
(Don't be tempted to use polystyrene instead of Kingspan; K'span has a far better insulation value).
If you're putting chipboard flooring back, use the proper annular nails ,or screws; ordinary oval or round wire nails gradually work loose and the chipboard squeaks.
If your joists are more than 4" deep, just hammer a few nails in the sides of the joists at a depth which will support the thickness of Kingspan you use. If they are 4" or less, you will need something like netting stapled to the sides of the joists to hold the Kingspan. The K'span is easy to cut with a saw.
(Don't be tempted to use polystyrene instead of Kingspan; K'span has a far better insulation value).
If you're putting chipboard flooring back, use the proper annular nails ,or screws; ordinary oval or round wire nails gradually work loose and the chipboard squeaks.
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1. you can lay a 1200 gauge polythene membrane over the oversite (earth). Try and lay it in one piece,lapping up the brickwork 100 - 150mm.This will act as a moisture barrier. There's no need to buy a roll, builders suppliers will often cut a length from a roll.
2. Why are you replacing all your floor boards - (and not the joists)?
I've been in properties that have 300 year old floor boards in-situ.
3. Research on this forum ref. inspecting your joist tails/bearings.
4. Do you have pipework or cables running on, thro or below the joists?
2. Why are you replacing all your floor boards - (and not the joists)?
I've been in properties that have 300 year old floor boards in-situ.
3. Research on this forum ref. inspecting your joist tails/bearings.
4. Do you have pipework or cables running on, thro or below the joists?
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