Cross Laminated Timber and other Engineered Materials

[puntloos]

My use case:

 

I'm 80% sure I want Timber Frame in the first place. But I have a few concerns (that will probably have to be addressed regardless of construction method, but let's take TF as a starting point):

 

1/ Acoustic Properties

• Nothing other than a meter of concrete will be perfect here, but I want to reduce sound travelling as much as possible between in particular my home cinema and any (bed)rooms above it.
• I think there's a lot of 'layering' needed, so perhaps the main materials are not that important.

 

2/ Creakiness/movement. 

• Creakiness is mainly (?) due to wood's natural movement properties in particular if it gets wet.  Once it moves, other things layered on top of it will start to shift&creak.
• This is where Cross Laminated Timber was suggested. It has much less movement

 

3/ Heat characteristics.

•  Providing mass to the building, ideally with large capacity to absorb heat before its temp rises, seems helpful here.
• Mass needs support - stronger joists, perhaps stronger, more rigid building materials.. 

 

4/ Underfloor heating

• Primarily a combination of the above concerns
• If you want to add mass, e.g. screed to lay the UFH in you need to be able to carry it 
• If your material moves/creaks it could have some impact on the UFH (this has been mostly debunked by the forum here, but I'll leave it as a small note)

 

The material type that seems most helpful here is something pretty rigid.. would CLT be a good candidate? What are the downsides? And more importantly perhaps, are there any actual TF companies that can work with them and provide a CLT-based timber frame in the first place?

[SteamyTea]

19 minutes ago, puntloos said:

I want to reduce sound travelling as much as possible between in particular my home cinema and any (bed)rooms above it.

I am not going to get too deep into this, but when I went to Jeremy's house while he was building it, the one thing that amazed me, more than anything else, is that it was very quiet.

It had none of that echo that half finished houses have.

If internal walls were constructed similar to the external ones, then sound transmission may not be a problem.

Worth investigating I think.

[ragg987]

41 minutes ago, puntloos said:

I think there's a lot of 'layering' needed, so perhaps the main materials are not that important.

Room within a room. And attention to detail both at spec and build. Lower frequencies especially benefit from mass of construction materials.

[Jeremy Harris]

23 minutes ago, SteamyTea said:

I am not going to get too deep into this, but when I went to Jeremy's house while he was building it, the one thing that amazed me, more than anything else, is that it was very quiet.

It had none of that echo that half finished houses have.

If internal walls were constructed similar to the external ones, then sound transmission may not be a problem.

Worth investigating I think.

 

You weren't alone, everyone that visits for the first time remarks on the quietness inside.  It's a bit eerie at first, but we love it now we're used to it.  A large part of the sound attenuation comes from the thickness of the walls and roof, the relatively high density of the cellulose insulation and the high degree of sound attenuation it provides.  We had no idea it would be like this until the house was built, as it wasn't something I'd given much thought to, as the village is pretty quiet anyway, but it is definitely nice to have as a bonus feature.

[Ferdinand]

1 hour ago, puntloos said:

1/ Acoustic Properties

• Nothing other than a meter of concrete will be perfect here, but I want to reduce sound travelling as much as possible between in particular my home cinema and any (bed)rooms above it.

 

Weekend cottage in Norfolk for 25k? With 700sqm of land. Plumbing, elec, internet already connected.

 

https://www.edp24.co.uk/edp-property/brundall-nuclear-cold-war-bunker-for-sale-1-6258802

Edited September 8, 2019 by Ferdinand

[MikeSharp01]

4 hours ago, puntloos said:

The material type that seems most helpful here is something pretty rigid.. would CLT be a good candidate? What are the downsides? And more importantly perhaps, are there any actual TF companies that can work with them and provide a CLT-based timber frame in the first place?

We are using Fin Joists  (FJI). these use cross laminated timber, thick plywood, for the flanges of the joists and OSB for the webs. This makes them dimensionally very stable and weight for weight (I won't use mass in case...) stronger / stiffer / able to span longer gaps.... We also have a large number of KERTO (CLT) beams as the major structural elements - Ridge beam etc. We went for engineered timber for a number of reasons:

 

1. We liked the idea of using sustainable materials. 
2. We wanted as much of the frame to be as dimensionally stable as we could make - I hate the way wood straight from the tree is able to warp, swell, shrink etc.
3. To my engineering mind I wanted to keep the structure simple and open which is easier using I beams than SIP panels.
4. Cost was an issue but because I am the major source of labour on our build I wanted something I could manage without help and that suited my limited ability with the wet trades - Brick/Block laying in particular.
5. Thermal performance and simple foundations as a deep and lightweight frame provides the ideal structure for a lot of insulation with limited cold bridging that can sit on a simple (relatively) passive slab.

Although I am doing it myself we spoke to a number of TF assembly companies and they were all happy to work with the FJI joists & KERTO beams.

Edited September 8, 2019 by MikeSharp01

[ProDave]

Ah the old "creaky, wobbly timber frame" myth again.

 

Well my house is timber frame and not a creak or wobble to be found anywhere.

 

I am sure we have all seen for example creaky floorboards and joists that sag as you walk on them.  This is just poor joinery or rotten / wrong spec joists.  There is no reason a properly built timber framed house will be creaky or wobbly.

 

And one feature of a timber frame house is they have lots of space to fit lots of insulation and the result is they are usually very quiet houses.

 

A cinema room if you are going to have loud sound and want other rooms to remain quiet is going to want special attention whatever build method.  Perhaps the most important question is WHERE to put it.  Backing onto the utility room and plant room would be far better than backing onto a bedroom.

[Patrick]

+1 on all that @MikeSharp01
said. In regards to the cinema room, apart from regular sound insualtion, just have a look at room in room system they use for Music studios, this works very well and should do the job in case your concerned a regular soundproofing in a timber frame won't be enough.?Edit:just seen that @ragg987

 suggested the same thing, so +1 on that as well

Edited September 8, 2019 by Patrick

[Temp]

3 hours ago, puntloos said:

I want to reduce sound travelling as much as possible between in particular my home cinema and any (bed)rooms above it.

 

I would consider something like a false ceiling. Eg don't fix the plasterboard to the underside of the floor joists, instead use separate joists to support it. Perhaps two layers of plasterboard. No lights penetrating the plasterboard?

[Patrick]

7 minutes ago, Temp said:

 

I would consider something like a false ceiling. Eg don't fix the plasterboard to the underside of the floor joists, instead use separate joists to support it. Perhaps two layers of plasterboard. No lights penetrating the plasterboard?

http://www.domesticsoundproofing.co.uk/soundproofing/rbar.htm

(stole this from another topic, just can't remember who posted it first)

[Archer]

CLT is a fantastic product and is slowly gaining traction across larger developments as a sustainable alternative to mass RC concrete frame (or at least was until the Hackett Review). It's in larger buildings and blocks of flats where most of the advantages shine, because it performs in a similar way to concrete in many respects, whilst having the advantages of prefabrication and locking up significant embodied energy. So advantages against traditional timber frame include the ability to build much higher structures up to 12 stories or more, dimensional stability, better fire and acoustic performance. Also the ability to leave certain elements of the structure exposed for the design effect of exposed timber (eg. CLT stairs and walls etc). It's a dream for architects to work with. 

 

Definitely has draw backs as well as others have said above. Traditional timber frame is a more efficient way of building with better strength to weight ratio - so much cheaper to buy and transport materials. Getting suppliers for a single CLT house would be difficult or expensive I'd have thought. Timber frame can also be improved by using engineered timber, added mass,  acoustic design etc and will still be much cheaper than CLT. 

 

Just on your point about acoustics, I wouldn't assume that bare CLT walls or floors will prevent sound transmission without lots of added layering either. You can look up standard details by googling it, but there were quite a few issues on early CLT residential blocks. Wood has less mass than concrete of the same thickness and so needs some help to prevent sound. 

 

Go for it if you like the material - send Buildhub some pictures of your finished house, it will be stunning!

[SteamyTea]

28 minutes ago, Archer said:

locking up significant embodied energy

Do you mean that, or embodied carbon?

[Archer]

Apologies, I mean't embodied carbon

Edited November 3, 2019 by Archer
Correction