Cutting thermalite blocks

[Pocster]

Thanks for all the advice 

my SE is too busy appearing on grand design and my architect - well ; he's been paid and gone .

good isn't it ?!

will get block work up to damp course then sort a company to spec structural timber and roof structure .

i do genuinely appreciate the help - and my lack of knowledge is due to not building before and having no support .

 

cheers all 

Edited March 31, 2017 by pocster

[Ian]

31 minutes ago, pocster said:

Thanks for all the advice 

my SE is too busy appearing on grand design 

Lol! ?

Quote

will get block work up to damp course then sort a company to spec structural timber and roof structure .

Good luck and let us know how you get on with the timber frame spec etc.

 

Ian

Edited March 31, 2017 by Ian

[Triassic]

Regarding the timber frame, theyshould do all the structural calcs and drawings for you. One less thing to worry about!

[Declan52]

If you use full fill cavity boards to insulate it will be dead easy to build. Your frame should be plumb so the boards you put against the frame will be plumb and then the blocks will be plumb. 

Only have to keep your eye on your coursing heights which as you will  have the boards already in will be a great guide to build to. 

[Roundtuit]

Can you full-fill the cavity? I thought the cavity was necessary for a timber frame with a masonry outer skin?

[Construction Channel]

2 hours ago, pocster said:

Thanks for all the advice 

my SE is too busy appearing on grand design and my architect - well ; he's been paid and gone .

good isn't it ?!

will get block work up to damp course then sort a company to spec structural timber and roof structure .

i do genuinely appreciate the help - and my lack of knowledge is due to not building before and having no support .

 

cheers all 

 

Just so you can read through it i will explain what i built, and in this case i think it will explain both sides of your coin (your builder friend seriously needs to think about his advice)

 

I dug footings, the front side needed re-bar as it was so close to the pond but don't worry about that, the back side need underpinning because planners are a PITA but also don't worry about that, essentially i ended up with a flat concrete surface that i could build my building off. 

 

then i built both skins up to damp,

 

then i filled the cavity with concrete so the top of said concrete sloped outwards (approx 40 DEG) with the inside edge of that concrete being 150mm below damp,

 

my front wall was a standard (ish) timber frame with brick skin construction, so first course on the outside above DPC had periodic weep vents to allow any water out, inside course lapped the DPM with the DPC and then bedded my sole plate on top. 

 

inside skin had a timber frame on it (studs clad in OSB then breather membrane on the outside) built in panels, outside was just 4" brickwork with cavity trays, lintels and timber fillets above openings all tied together with "wall ties" (screwed through the OSB to the studs every 6 courses (2 courses on blockwork) and every 3 on reveals)  (not every stud but there is no reason to skimp on things like this)

 

simples

 

back wall was a whole different kettle as i had to leave the original wall standing for planning reasons but it is worth noting it was a 9" wall (technically structurally free standing)

 

in this case I built the panels on the floor, plied and covered them in membrane as separate sections then erected them (obviously leaving a cavity) against the existing wall,

I will tie the two together as much as i can when i create the new openings. i would be mad not to. But If i wasn't creating new openings there would be no way to tie them together which is acceptable as it is 9" but IMHO is not a great idea.

 

I have been drinking so I'm sure this won't sound as comprehensive in the morning as it does now but feel free to have a look through my videos, i might not explain much of it but it is all there if you look hard enough,

 

I should note I am not insulating my cavity at all. all of my insulation is within my timber frame or inside it

 

Ill probably edit this in the morning.

 

HTH ED

[Brickie]

9 hours ago, pocster said:

 

will get block work up to damp course 

I'd even hold fire on that-your internal block work will need to spot on (or near as dammit) to receive the sole plate for the frame. You'll need a laser level for this & I'd get a competent brickie in for this as it's critical. The height of the sole plate will be relative to your ffl (you should have a drawing sowing this detail) & external Dpc should be same as ffl. Any rises or drops in external g/l can be dealt with by additional lapped Dpc,&,in the case of your front elevation with the concrete roof detail,a dpm wrap around detail might be the way to go. All in all,you need to be armed with a lot more info,levels wise. Iirc,you're building abuts an existing structure? In which case,can you post your ground floor make up drawings?

From that,between us all we should be able to give you a height for ffl,which you can mark 1m above on your existing structure. All subsequent work can then be referred against this datum,to keep you on track. 

Btw,the concrete structure for the basement walls-was it poured in one hit with waterproof concrete?

[Pocster]

Thank you so much all

 

my project ground to a halt many months ago due to personal and financial issues .

i *think* I understand what to do so will post my thoughts so you guys can check I'm  on the right line . Will upload some plans .

my se and architect were on board until a few months ago and bco has checked everything to date . So I don't think I've done anything insanely stupid yet . Am away this weekend enjoying a much needed break - will post with details and questions later tomorrow.

you guys saved me ! Each gets a crate of beer if you are down Bristol way !!!

Edited April 1, 2017 by pocster

[Pocster]

Hey all!

 

Right!

Here's what I *think* and also some questions. Please if answering quote the point that's wrong or you think might be wrong.

Any help is appreciated!!!

 

1) The thermalite external skin doesn't really do a lot except be something to render and keep the rain out

 

2) The thermalite skin is tied across the insulation to the inner timber frame which is structural. Hence why timber frame *must* be erected first! (I get it now! - didn't know this until you guys said).

 

3) Inner timber frame has presumably 4 base plates (per corner?) ; these need to be positioned accurately . I assume these attach straight to the beam and block?

 

4) Inner timber frame is built and clad in OSB or similar ; this in turn covered with some membrane (air/water proof). So essentially you end up with a timber 'box' clad in membrane. Which is turn the roof structure sits on.

 

 

 

 

Questions!

 

1) If internal timber frame is structural ; does nothing go inside the frame? i.e. the insulation is outside this; so just a void?

 

2) Say (for example) to run a pipe or electrical wiring from front of ground floor to back would require drilling through the timber frame!. I presume a 'few holes' potentially every 'upright' is not an issue??

 

3) DPC confuses me. I thought the general rule was 150mm above external level. But I think Brickie mentioned it's kind of relative to your inner floor finished level. So on this basis do I assume the DPC is about the same height as the finished internal floor level (as long as externally it's at least 150mm)?

 

4) The ground floor at the rear of the build has a sunken garden effectively - so no DPC required for the back wall? (perhaps just a bit on the returns?)

 

5) If you look at the photo (not plans) you'll see I had to build a single skinned concrete block wall. This is tied on the outside to stone work. Errecting the timber frame/ cladding and membrane externally wouldn't be possible at this point. The wall is at full height so assume tieing from above that to the frame would be fine; i.e. the wall at this point is self supporting.

 

6) Although the SE/architect/BOC have inspected everything - they all (including myself!) missed that there is no DPC on this wall mentioned in question 5). Any suggestion on how to retrospectively fit a DPC???. I'm not sure how much rain splashing or rising damp this block work would get in reality - but worth asking!

 

7) As mentioned my SE is too busy and my architect has run away (thanks guys!). The timber frame design and spec I'll get a firm to do. I assume BOC will be happy with this. Do I need BOC to check more things at certain intervals now there is no architect on board??. I want the finished build to pass :-)))

 

 

Edited April 2, 2017 by pocster

[Pocster]

 

 

 

 

 

Edited April 2, 2017 by pocster

[Construction Channel]

4 hours ago, pocster said:

1) If internal timber frame is structural ; does nothing go inside the frame? i.e. the insulation is outside this; so just a void?

 

I would put some insulation in there if you can afford it. I assume you have already achieved your U values in the cavity but it probably won't hurt to improve on it.

4 hours ago, pocster said:

4) Inner timber frame is built and clad in OSB or similar ; this in turn covered with some membrane (air/water proof)

 

this wants to be breathable, if this part is waterproof e.g polythene your frame will "sweat"

 

4 hours ago, pocster said:

2) Say (for example) to run a pipe or electrical wiring from front of ground floor to back would require drilling through the timber frame!. I presume a 'few holes' potentially every 'upright' is not an issue??

 

i would try to utilise your ceilings if possible. you may be able to run you pipes in the screed but I usually see them put in between the ceiling joists. (if you have B&B you may need to add a service void below)

 

4 hours ago, pocster said:

5). Any suggestion on how to retrospectively fit a DPC???.

 

black splash the whole thing (paint it with a couple of coats of liquid waterproofer,) there will be other ways to do this part but i recon this will be the cheapest option.

 

IDK about the rest but i hope that helps 

[Brickie]

1/ it's a long time since I worked on timber frame but every single one I have had the cavity empty. Weep holes were built in at the bottom (on the cavity tray) & near the eaves to create a ventilated cavity. The 'norm' may well have changed since then so worth looking into. 

3/ you need Dpc all the way round for it to be effective. As I mentioned above,it used to be the norm to fix a cavity tray at ffl,if not then 100mm damp all the way round,with additional stepped down (& lapped) to 150mm above dropped ground level.

 

When the time comes we can go over exactly how to install a tray,also care need to be given to propping lintols & cutting blocks to go across them. By God,thermalises love to bow out over openings,esp on tf. 

We had to put bed joint reinforcement (brick tor or train track) for two courses below & above all openings,to minimise movement & prevent cracking. Again,worth researching if this practice has been superseded. 

[Pocster]

Thanks for all the replies.

Just awaiting some responses from timber frame suppliers......

 

Cheers