Laminate/ lvt/ underlay combinations - best way to insulate cold floor

orangecrush

Hi savers,

We have an elevated room, that sits about 5 feet above the (sloped) garden. It has no insulation under the sub floor. We don’t have the time to pull it up and insulate, and there’s no access from the crawl space. 

Instead we want to put down some thermal underlay and either LVT or laminate on top - it will be a kids playroom that goes out to the garden so carpet is not practical. 

The complication: it has a sliding door, with limited ground clearance. I had found some 5mm thermal underlay with 2.2tog rating, but that plus 8mm laminate means the patio door won’t open. 

My options are:
1: Thinner underlay with 1tog, plus 8mm laminate (cheaper, nicest floor, bit less insulation) 
2: 5mm thermal underlay with 6mm laminate (cheaper, more insulation but not as nice floor)
3: 5mm thermal underlay with 4mm LVT (most expensive)

What I can’t figure out is whether there will be a noticeable difference in 1tog vs 2tog, when combined with a floor. The difference in cost between options 1 and 3 is around £200, for a 10sqm room. Is it going to be £200 warmer? The room is south facing and is heated, but on winter mornings it’s flipping freezing on your feet, even with slippers.

Any thoughts gratefully received! 

ChilliBob

This is quite an 'out there' idea, but I believe bathroom underfloor heating is often done with these heat mat things? I wonder if these would be thinner, and provide more heat?

Family heater slippers, if these are a thing!

I have seen thin laminate look rubbish very quickly, if it's a play room connected to the garden it sounds like it'll get mashed, so perhaps the thicker sfuff is better.

Out outhouse had those thick gym mats that link together, they might be warmer? 

orangecrush

I really wanted to add underfloor heating mats but my husband is not keen. Also the cost is an issue, not so much of running it but of buying it; we’re reaching the top of our budget for this room and I want to get thermal blinds too (another post for another time).

I agree about the cheap laminate… maybe just go for the thinner underlay and buy a good rug? 

FreeBear

Laminate can be quite noisy under foot and is not always easy to clean - You need to be careful mopping it, as some brands don't like to get wet.

I have LVT (click type) over wood fibre boards in the kitchen and a foam underlay (polystyrene) in the utility - Both areas are uninsulated concrete floors. There is less noise underfoot in the utility but there doesn't seem to be any difference in floor temperature - Both surfaces are a little warmer that the original lino laid straight on top of the concrete.

I wouldn't get too hung up on the advertised tog rating of any underlay. At just 5mm thick, it won't provide much in the way of insulation. It is going to boil down to which one feels better - For my money, I'd go for https://www.screwfix.com/p/diall-extruded-polystyrene-foam-underlay-5m/1583r

Bendy_House

orangecrush said:

Hi savers,

We have an elevated room, that sits about 5 feet above the (sloped) garden. It has no insulation under the sub floor. We don’t have the time to pull it up and insulate, and there’s no access from the crawl space. 

Instead we want to put down some thermal underlay and either LVT or laminate on top - it will be a kids playroom that goes out to the garden so carpet is not practical. 

The complication: it has a sliding door, with limited ground clearance. I had found some 5mm thermal underlay with 2.2tog rating, but that plus 8mm laminate means the patio door won’t open. 

My options are:
1: Thinner underlay with 1tog, plus 8mm laminate (cheaper, nicest floor, bit less insulation) 
2: 5mm thermal underlay with 6mm laminate (cheaper, more insulation but not as nice floor)
3: 5mm thermal underlay with 4mm LVT (most expensive)

What I can’t figure out is whether there will be a noticeable difference in 1tog vs 2tog, when combined with a floor. The difference in cost between options 1 and 3 is around £200, for a 10sqm room. Is it going to be £200 warmer? The room is south facing and is heated, but on winter mornings it’s flipping freezing on your feet, even with slippers.

Any thoughts gratefully received! 

I don't understand how a slightly raised floor will prevent a SLIDING door from opening - could you explain, please?

Anyhoo, I would suggest, in principle, the thicker the layer of insulating underlay relative to the floor covering the better, so perhaps start from - what's the THINNEST flooring you have available to you, and then choose the thickest U/L to suit. Some won't go with others, of course.

What is the existing floor made from? Are there any gaps in the joints? Around the perimeter under the skirting? If so, seal all these first.

There is a 5 or 8mm thick low-dens fibre board underlay that's used with laminate - I'd suggest that this would offer a noticeable level of useful insulation, tho' I don't know what other coverings it can be used with.

The doors - if you actually meant that they were conventional hinged doors, so swing over the floor, then is a possibility that you could leave a lower 'well' for this swing, and raise the rest of the floor a good inch or so? Ie to a level that will provide a noticeable level of insulation? The 'well' would be thinner, and such a step would not normally be acceptable, but this is a playroom, and on the exit - so 'could' be quite liveable-with?

orangecrush

FreeBear said:

Laminate can be quite noisy under foot and is not always easy to clean - You need to be careful mopping it, as some brands don't like to get wet.

I have LVT (click type) over wood fibre boards in the kitchen and a foam underlay (polystyrene) in the utility - Both areas are uninsulated concrete floors. There is less noise underfoot in the utility but there doesn't seem to be any difference in floor temperature - Both surfaces are a little warmer that the original lino laid straight on top of the concrete.

I wouldn't get too hung up on the advertised tog rating of any underlay. At just 5mm thick, it won't provide much in the way of insulation. It is going to boil down to which one feels better - For my money, I'd go for https://www.screwfix.com/p/diall-extruded-polystyrene-foam-underlay-5m/1583r

Thanks that’s one of the ones I’ve got on my shopping list! You’re probably right about the laminate being noisy; we have it in the hallway but it’s a small space so we haven’t noticed undue noise. But the wet aspect - yes. Maybe LVT is the way forward. The £200 extra may be worth it when I’m not dashing round with a mop every time the kids come in! 

orangecrush

Bendy_House said:

orangecrush said:

Hi savers,

We have an elevated room, that sits about 5 feet above the (sloped) garden. It has no insulation under the sub floor. We don’t have the time to pull it up and insulate, and there’s no access from the crawl space. 

Instead we want to put down some thermal underlay and either LVT or laminate on top - it will be a kids playroom that goes out to the garden so carpet is not practical. 

The complication: it has a sliding door, with limited ground clearance. I had found some 5mm thermal underlay with 2.2tog rating, but that plus 8mm laminate means the patio door won’t open. 

My options are:
1: Thinner underlay with 1tog, plus 8mm laminate (cheaper, nicest floor, bit less insulation) 
2: 5mm thermal underlay with 6mm laminate (cheaper, more insulation but not as nice floor)
3: 5mm thermal underlay with 4mm LVT (most expensive)

What I can’t figure out is whether there will be a noticeable difference in 1tog vs 2tog, when combined with a floor. The difference in cost between options 1 and 3 is around £200, for a 10sqm room. Is it going to be £200 warmer? The room is south facing and is heated, but on winter mornings it’s flipping freezing on your feet, even with slippers.

Any thoughts gratefully received! 

I don't understand how a slightly raised floor will prevent a SLIDING door from opening - could you explain, please?

Anyhoo, I would suggest, in principle, the thicker the layer of insulating underlay relative to the floor covering the better, so perhaps start from - what's the THINNEST flooring you have available to you, and then choose the thickest U/L to suit. Some won't go with others, of course.

What is the existing floor made from? Are there any gaps in the joints? Around the perimeter under the skirting? If so, seal all these first.

There is a 5 or 8mm thick low-dens fibre board underlay that's used with laminate - I'd suggest that this would offer a noticeable level of useful insulation, tho' I don't know what other coverings it can be used with.

The doors - if you actually meant that they were conventional hinged doors, so swing over the floor, then is a possibility that you could leave a lower 'well' for this swing, and raise the rest of the floor a good inch or so? Ie to a level that will provide a noticeable level of insulation? The 'well' would be thinner, and such a step would not normally be acceptable, but this is a playroom, and on the exit - so 'could' be quite liveable-with?

Thanks Bendy! The sliding door is annoying. The room is a conservatory, so it has external doors between the dining room and the conservatory itself. (I am tempted to ditch them but want to have a winter with the conservatory with its new roof, to see how cold it gets). The sliding door is on a slightly raised rail, and the fascia of the door overhangs the rail. We’ve tried with different thickness samples and it can JUST handle 10mm, anything more it won’t go over. 

The sub floor is plywood, I can’t tell how thick without pulling bits up. It has glued down vinyl on top. There is only 2mm to be had from removing the glued down vinyl, so I was tempted just to put the new floor on top of it 🙈 Awful idea?

The are definitely gaps around the edge to fill! The last owners seem to have put the skirting on blindfolded so it is all over the place. So that’s on the to-do list too.

The well idea is an interesting one! I’ll do a few tests with our samples and see how close I can get the underlay to the door under the laminate. My concern would be whether that would put pressure on the joins between the planks. 

I think the thickest underlay with thinnest floor is probably the best bet - the LVT is nice, and seems kid-proof. We fitted it in our last house with concrete floor and it was great, I just didn’t want to spend so much this time round. But maybe I’m being cheap on the wrong things 🤔 

FreeBear

orangecrush said: The sliding door is annoying. The room is a conservatory, so it has external doors between the dining room and the conservatory itself. (I am tempted to ditch them but want to have a winter with the conservatory with its new roof, to see how cold it gets).

The are definitely gaps around the edge to fill! The last owners seem to have put the skirting on blindfolded so it is all over the place. So that’s on the to-do list too.

Leave the door in place between the house & conservatory - It should be an exterior grade door, and keeping it shut during the winter will do wonders with your heating bill. Conservatories, even with decent glass and an insulated roof will suck out heat from the rest of the house. They don't have to comply with Building Regulations as far as thermal performance is concerned, and all that glass won't help.

Skirting, I would recommend taking it off all the way round. Fit your flooring and leave an 8-10mm gap around the perimeter (snug up to the doors). When you refit the skirting, it will hide the gap between flooring & wall - The gap is needed to allow the laminate/LVT to expand/contract.

Bendy_House

OrangeC, I still don't understand the sliding door issue - any chance of a pic?

As FB says, it's much better to remove and redo the skirting boards OVER the new flooring, but allow that expansion gap depending on flooring type.

More than that, tho' - make sure there isn't a draughty-gap between the perimeter of the EXISTING flooring and the wall. If there is, use something cheap like frame sealant to seal it, or even a careful bead of expanding foam if it's larger. Draughts are the enemy

ANYTHING extra you add to the floor - even 5mm's worth - will have a useful effect, and likely quite noticeable too.

orangecrush

The door is exterior grade, but the last owners lost the key and it is a bit wonky; this isn’t our forever house so didn’t want to invest in a new door, but maybe we should…

And thanks for the advice on the skirting! We’ll definitely do that. We’ve just done our hallway but couldn’t remove the skirting (original to the house) so just used expansion strips and then beading trim. It seems to do the trick in the hallway. But the skirting in the conservatory is definitely worth fixing! I don’t know how the last owners lived with it so higgledy piggledy. 

orangecrush

Bendy_House said:

OrangeC, I still don't understand the sliding door issue - any chance of a pic?

As FB says, it's much better to remove and redo the skirting boards OVER the new flooring, but allow that expansion gap depending on flooring type.

More than that, tho' - make sure there isn't a draughty-gap between the perimeter of the EXISTING flooring and the wall. If there is, use something cheap like frame sealant to seal it, or even a careful bead of expanding foam if it's larger. Draughts are the enemy

ANYTHING extra you add to the floor - even 5mm's worth - will have a useful effect, and likely quite noticeable too.

I’m at work but when I get home I’ll take a pic! I’m not very good at describing… maybe I can draw it 🤣