Thorfun

And all my overthinking was in vain as I cannot find sound blocking plasterboard in 900x1800 sheets. I can’t fit standard sized boards down the stairs to the basement so looks like I’m just going to have to use double skin of standard plasterboard and live with any noise that gets through. 😢

I agree with @nod. We didn’t use a main contractor and just hired subbies. None of them had contracts they just quoted for the work and did the job. but maybe we were lucky and got really good trades who were all spot on and so there weren’t any disputes.

That’s really interesting especially as Fermacell alone says it can take 30kg per screw by itself! I wonder if I’m overthinking it all as usual and for a couple of really heavy fixings just use multiple of those big bad-ass plasterboard fixings (https://www.gripitfixings.co.uk). They state 113kg which is more than a speaker for a PA system.

https://www.british-gypsum.com/products/board-products/gyproc-habito-12-5mm#characteristic 15kg a screw. Thanks. Will keep it in mind.

Interesting. Will research it as I’ve never heard of it.

I will use Rockwool behind the boards and green glue around edges and fittings to help.

good to know! thank you. 🙂 I assume fixing OSB or Ply to metal frame isn't hard?

hmm....maybe a layer of fermacell with Soundbloc on top would be better than ply with Soundbloc on top?

my thoughts are slowly turning to kitting out the basement and I think the first room I'll do is our music room so I can start playing musical instruments again! I need to soundproof a lot to reduce the noise carry of drums and electric guitars/bass etc. I was going to double skin with soundbloc but I was wondering what the hanging capacity of it is and whether I should do a layer of 18mm ply and then Soundbloc on top so that I can fix things to the walls without worry of them falling off. I'm thinking things like a PA, guitars, instruments, speakers etc. I'll be using metal frame to build a room within the room to reduce vibrational sound transfer and the Soundbloc will attach to that rather than dot and dab on to the concrete/blocks. anyone got any thoughts on this please? ps. before anyone mentions that the doors will be the weak point I am planning on having double-skinned doors, one inward opening and other outward opening with an air gap between to help reduce noise transfer through the doors.

+1 to considering getting new plans drawn up and resubmitting planning. that way you get exactly what you want not what the seller of the plot used to get through planning. yes, it'll add 6 - 12 months to your schedule but think it'll be worth it. Also +1 to the number of bedrooms. unless you need them that is. we have 2 kids and built a 3 bedroom house with big bedrooms. yes we could've fitted 5 bedrooms in the same space but didn't want to end up with pokey bedrooms with 2 spare rooms that would rarely be used. obviously with a house your size these things aren't so important i guess but i'd rather my kids had space to enable them to stay well in to adulthood if required so there was space for them and partners.

in that case have you thought about running the cable to an external enclosure with a garage CU in it? you can then use that external feed to power the STP and also have another fuse free for external power sockets or driveway lights etc? might save having to run another cable in the future? 🤷‍♂️

Wow! That’s one heck of an ambitious project and a stunning design. I wish you all the best with it. looks like most of the building is built into the landscape so concrete really is the only way. The above ground bit could be timber frame if you wanted a change of materials. prefab concrete panels will be quick but expensive. Formwork and pouring concrete surrounded by EPS would be cheapest I imagine but will take longer. ICF might be comparable but you’d need to get quotes and SE drawings that are ICF specific afaik. checkout the basement forum as that’s pretty much what you’re building. There are many ways to do it and it all depends on what works for you and your budget.

First time for everything

Not that I remember. We only used Jackoboard in the wet zones and the tiler applied a painted product as a sealer. Don’t recall scrim tape being used at all.

I want to fix something to our Evalon VSK covered flat roof using CT1. I asked Alwitra technical and the response was (paraphrasing) “we haven’t tested with that product. Although we don’t anticipate any issues we can’t say it’s safe to use” so basically arse covering. anyone got any thoughts on whether CT1 will compromise my roof covering?

very true. you just have to read the threads on this site to know that it seems very finger in the air! one person will have a low quote and another a high quote from the same company. it's as if they price as to whether they actually want the job or not. we had a big spread of quotes for our windows including vast differences in the same Internorm windows from different companies.

an inspiration to us all

yes but for us the fact that it was all managed by Norrsken meant there was no finger pointing if things went wrong. sometimes you can't put a price on that peace of mind. Also (assuming it's still the same company) the guys they use for the installation were top! can't recommend them highly enough. their name is in my blog somewhere i'm sure.

you are the master of cowboys!

the problem is that every vent has a route to the outside, right? and you can't close off the vents of each individual room as they're fixed in place to ensure the correct flow rates. i guess you could cover them in an airtight material somehow. maybe your tester will know of a way

oh. 😞 ours were easy access.

we just left keys in the locks of the doors and sliders. can't remember if we bothered with the window keyholes

it's actually quite interesting how much of a difference fixing a really small hole makes when you start getting to very low levels. but i wouldn't worry about the walk-on glazing. the levels you're after unless water is gushing in you'll be fine.

ours wasn't commissioned at the time so we just blocked off the external incoming/outgoing vents. we taped airtight membrane to them. i wouldn't bother with closing off all internal vents tbh. just block the route to the outside and job done. also need to block off soil vent pipe and any bathroom fixtures that haven't got water in the trap. basically any hole that leads to outside.

if all you want to do is pass then i think the value might still be 10ACH? (someone can correct me if i'm wrong) as building regulations suck. i believe that anything below 5 requires MVHR so anything above that then you've wasted your money on MVHR. the lower it is the better it is. your place is a concrete box, right? so should be pretty low. good luck!