Anyone done external insulation (sound & heat)?

[mancity68]

Our house has a carriage arch ie a drive underneath our bedroom to get through to the house behind us. With this empty space underneath us, the room is quite often freezing and it acts as an echo chamber for noise coming from the house next door (and the car driving through. We want to add thermal and sound insulation. We can either remove all of the furniture, take up the floorboards and try and add the insulation from inside, but this feels like a big job.

So I was wondering if we could insulate from the outside ie affix some form of insulation panels to the ?ceiling? of the driveway.

Has anyone done anything like this? Any thoughts on product eg Rockwool maybe? And/ or any thoughts on insulation experts?

Thanks!

[HensloweMum]

I don't know if I would do external. You say that taking up floorboards etc would be a bigger job than trying to do something externally but I don't actually think that's the case--it could end up being more work in the future trying to fix something you tried but then didn't work. I think taking up floorboards and putting in some really decent RWA45 rockwool is a good way to go. The problem trying to do external is keeping it dry. How would you do that without effectively building a proper ceiling and then waterproofing it? Suppose you could just have a go with some celotex or whatever and see what happens...

[KidKruger]

Also, if you have to deploy (and subsequently fix) exterior insulation you?ll likely be blocking the carriageway access to the other house you mention for the duration of that activity.

[diable rouge]

The sound you're hearing is probably coming through the structure (structure borne) as opposed to flanking (through open windows/doors) or impact, and it's difficult to eliminate if the property hasn't been built to prevent that from happening. The noise is probably reverberating up through your walls as well as the floor, so insulating the floor might not make a huge difference (recording studios get round this by building a box within a box, but that's way OTT for a domestic situation unless you thought it worthwhile).

However, you should get some benefit on heat loss side of things.

As an aside, have you considered putting in a bigger radiator? When the original was installed the installer might not have taken into account the room has an external soffit, so simply getting a bigger rad could help in that respect.

A photo of the arch would've been really useful, so in lieu of that I'm guessing that there's a recessed concrete soffit beyond the arch, similar to this (couldn't find a pic showing a curved arch)...

If this is the case then in theory it wouldn't be difficult to form a new floating soffit incorporating some sound/thermal insulation, finished with a smooth exterior board painted out. But it needs to be done professionally, probably with a vapour barrier and maybe even vents to prevent condensation build-up. And once you get into stuff like that, Building Control need to be informed and approval sought.

You will also need the permission of the management company/freeholder or the owner of the other property(ies) if it's a share of the freehold, to carry out the works.

If the arch is continuous i.e. no recessed soffit, then I'd forget about it, as visually it would look a mess.

I also think it would be less hassle to do add some insulation internally. You don't mention lifting up carpets, just moving furniture and lifting floorboards. So it may be a simple case of putting down a really thick heavy duty underlay and carpet, sealing any gaps e.g. between floorboards ands skirtings, with mastic.

Personally, I'd try that first, along with a new rad, and see if that works before attempting lifting floorbaords etc

If not or you already have a carpet, then obviously you will need to lift it and the floorboards and run some insulation between floor joists, this can be the Rockwool type or rigid boards. There are lots of DIY videos on YouTube how to do both...

[redpost]

I very much doubt that EWI in a sheltered arch will need a vapour barrier let alone vents since it'll be 100% shielded from rain. If you are leasehold then I wouldn't bother with this solution.

As said, the easiest option is get your floorboards up.

If sound bothers you, then fill around 75% with high density mineral wool with air gap at top. Mechanically couple the joists with noggins at regular intervals, couple joist ends to brickwork securly with steel brackets and chemical fixing, discard the floorboards and top with a layer of 18mm ply on top well screwed down to joists. Basically mass and mechanically coupling the building copmonents are your friend in lowering the resonant frequency and reducing noise. Resonant frequency = 1/ (mass x area) ... larger the mass and coupled area, lower the resonant frequency and lower the noise.

If you want thermal insulation then 100% fill with PIR insulation (celotex/kingspan etc)

Pay attention to air tightness to stop windwash, squirty foam does the job.

Most builders are blaggers and won't have a clue about any of this.

[diable rouge]

redpost Wrote:

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> I very much doubt that EWI in a sheltered arch

> will need a vapour barrier let alone vents since

> it'll be 100% shielded from rain.

Because of the lack of detail/photos I was trying to cover all possibilities.

Despite the sheltered aspect, interstitial condensation could be a problem as condensation doesn't just form in areas exposed to rain.

I'm sure the OP is wise enough that if they decided to investigate an EWI solution they will contact the technical help line of a company like Rockwool/Kingspan etc, and get them to spec up a solution...

[mancity68]

Wow! Cheers all, really appreciated. Diablo, yes, it?s an arch broadly like the pic you posted. I am the freeholder so that bit is less problematic at least. Condensation both in the room above the arch and on the inner brickwork of the arch is a real problem simply because of the cold so anything that adds to issues will need pondering. Will contemplate feasibility of taking everything out of the room to do from within. And yeah, appreciate we?ll be getting the sound/vibration through the building structure as well as via floor....but every little must help!