Basic garden room insulated slab

[daiking]

3 minutes ago, Onoff said:

Great tool for roots:

 

https://www.toolstation.com/roughneck-mattock-with-fibreglass-handle/p20759?

tricky to use in a 30cm wide trench. 
 

I did sharpen my spade with a file before I started all this jazz which helped a lot. bigger roots I’m using a saw.

[Russell griffiths]

I know this was already discussed, but why the trench if you have root problems. 

A simple raft is what you need. 

Buy some scaffolding boards as shuttering, weekends work and it will be in. 

[Onoff]

10 minutes ago, daiking said:

tricky to use in a 30cm wide trench. 
 

I did sharpen my spade with a file before I started all this jazz which helped a lot. bigger roots I’m using a saw.

 

Not at all. I just dug a 13m trench with one, 600mm deep. No wider than 6". I started off with a pronged digging tool then gave up and switch to the mattock. A revelation. I had to go through conifer roots and clay. Sharp mattock blade will go straight through the roots if you hit 'em right.

 

 

Edited February 21, 2021 by Onoff

[daiking]

2 hours ago, Russell griffiths said:

I know this was already discussed, but why the trench if you have root problems. 

A simple raft is what you need. 

Buy some scaffolding boards as shuttering, weekends work and it will be in. 

becuz, becuz, becuz...

 

I want it insulated, I want it in the ground (PD height restriction) etc. Not got to a point where I’ve got second thoughts on cutting through something.

 

Saving my second thoughts for the opposite corner with there’s a 4” root of another tree about 1” beneath the surface. Can’t remember what that tree is but it’s a tiddler, only 12” diameter.

 

 

 

[daiking]

Was hoping to get the footings done this week but that’s not going to happen.
 

Still, if Boris pushes proper pub opening back to May, I’ll have plenty of time to sort it.

[daiking]

At least none of you have said that building so close to a tree it'll sink into the ground within 6 months.

[joe90]

59 minutes ago, daiking said:

At least none of you have said that building so close to a tree it'll sink into the ground within 6 months.

If laid with steel in it it will rise fall or tip as one piece if the worse happens (which is why I like adjustable ground anchors next to trees).

[HaggisEdi]

Hi,

Virgin post :]

All is looking good, however under the DPM you should really use XPS insulation instead of  EPS, which would change your budget a little bit.

 

100mm XPS on ebay would cost you £65+£25 delivery, thats for an area of 3m2.

 

Thanks

[daiking]

3 hours ago, HaggisEdi said:

Hi,

Virgin post :]

All is looking good, however under the DPM you should really use XPS insulation instead of  EPS, which would change your budget a little bit.

 

100mm XPS on ebay would cost you £65+£25 delivery, thats for an area of 3m2.

 

Thanks

Cheers. I’m a bit surprised by that as XPS is more expensive (on that basis) that PIR. 
 

I didn’t think there was a problem with a building grade eps? It’s for putting under slabs isn’t it?

[Bitpipe]

14 minutes ago, daiking said:

Cheers. I’m a bit surprised by that as XPS is more expensive (on that basis) that PIR. 
 

I didn’t think there was a problem with a building grade eps? It’s for putting under slabs isn’t it?

   

I have 140m2 of 300mm EPS 200 under my basement (so holding up my house). Not sure why XPS is considered better?

 

Bit late to change it now

 

[Onoff]

30 minutes ago, Bitpipe said:

   

I have 140m2 of 300mm EPS 200 under my basement (so holding up my house). Not sure why XPS is considered better?

 

Bit late to change it now

 

 

Can you dig under and swap it out? ?

 

https://www.constructionspecifier.com/comparing-polystyrenes-looking-at-the-differences-between-eps-and-xps/3/

[HaggisEdi]

From google:"When comparing EPS and XPS board densities, the compressive strength of XPS is greater than that of EPS." 

That's a great study:

Long-term water absorption tests for frost insulation materials taking into account frost attack - ScienceDirect

4. Conclusions

On the basis of the research the water absorption on XPS specimens is significantly minor compared to EPS specimens that were studied. The most significant result was that freezing of test specimens did not affect on water absorption of XPS specimens but had a major effect on water absorption of EPS specimens. With frozen EPS specimen the absorption continued increasing even after 48 months of immersion. Presumably the reason for such behavior is that the pore structure of EPS is not able to resist the tension caused by freezing water and therefore cracks are formed. Thus, more water gets absorbed inside the EPS through the cracks and it causes cracking deeper in the specimen which is why absorption increases after every freezing period.

 

But, I wouldn't be too worried, you should be fine in the garden room, 125mm sounds plenty to me.

[daiking]

11 hours ago, HaggisEdi said:

From google:"When comparing EPS and XPS board densities, the compressive strength of XPS is greater than that of EPS." 

That's a great study:

Long-term water absorption tests for frost insulation materials taking into account frost attack - ScienceDirect

4. Conclusions

On the basis of the research the water absorption on XPS specimens is significantly minor compared to EPS specimens that were studied. The most significant result was that freezing of test specimens did not affect on water absorption of XPS specimens but had a major effect on water absorption of EPS specimens. With frozen EPS specimen the absorption continued increasing even after 48 months of immersion. Presumably the reason for such behavior is that the pore structure of EPS is not able to resist the tension caused by freezing water and therefore cracks are formed. Thus, more water gets absorbed inside the EPS through the cracks and it causes cracking deeper in the specimen which is why absorption increases after every freezing period.

 

But, I wouldn't be too worried, you should be fine in the garden room, 125mm sounds plenty to me.

 

XPS is a better material. To be honest I should just have a dumb slab poured and use 50mm of PIR under the floating floor but I doing it the other way for shits and giggles. 

 

If I had any potential for a heat source, I'd put UFH pipes in the slab as well ? - which is one of the few jobs I have actually done myself in the past so can claim a limited amount of experience. 

[Bitpipe]

15 hours ago, Onoff said:

 

Can you dig under and swap it out? ?

 

https://www.constructionspecifier.com/comparing-polystyrenes-looking-at-the-differences-between-eps-and-xps/3/

 

Sounds like an ideal summer project

 

[Onoff]

28 minutes ago, daiking said:

If I had any potential for a heat source, I'd put UFH pipes in the slab as well ?

 

Compost pile coupled with some small scale hydro?

[daiking]

12 minutes ago, Onoff said:

 

Compost pile coupled with some small scale hydro?

Think big, think GSHP

[Onoff]

4 hours ago, daiking said:

Think big, think GSHP

 

Borehole in your case I imagine?

[Gone West]

6 hours ago, daiking said:

If I had any potential for a heat source, I'd put UFH pipes in the slab as well ? - which is one of the few jobs I have actually done myself in the past so can claim a limited amount of experience. 

What about something like a 600W ASHP in a 100litre Ecocent.

[daiking]

I was not seriously suggesting I would put ufh in a 13m2 shed.

[daiking]

I think I’m dug out now. No idea on the level of the trench (I was wrong).

 

With nothing in particular to use I decided to pick the high point of external ground and hammer stakes into the bottom of the trench with the planned 150mm concrete depth marked on it. 
 

Then banged in another stake to the same level 850mm along the trench (I only had a 900mm level) worked my way round with lots of stakes and when I got back to the start, I did not have the same level ?.

 

I was planning on getting a 1800mm level anyway so got it. Did the same again and whilst the levels were a lot closer, was still a few mm out. 
 

so I’m expecting the concrete man to come and fill the trench with concrete up to the level of the top of the pegs. The variation in the level of the concrete will need to be overcome by the mortar bed under the concrete blocks. 
 

fingers crossed eh?

 

 

 

 

[Onoff]

1 minute ago, daiking said:

I think I’m dug out now. No idea on the level of the trench (I was wrong).

 

With nothing in particular to use I decided to pick the high point of external ground and hammer stakes into the bottom of the trench with the planned 150mm concrete depth marked on it. 
 

Then banged in another stake to the same level 850mm along the trench (I only had a 900mm level) worked my way round with lots of stakes and when I got back to the start, I did not have the same level ?.

 

I was planning on getting a 1800mm level anyway so got it. Did the same again and whilst the levels were a lot closer, was still a few mm out. 
 

so I’m expecting the concrete man to come and fill the trench with concrete up to the level of the top of the pegs. The variation in the level of the concrete will need to be overcome by the mortar bed under the concrete blocks. 
 

fingers crossed eh?

 

 

 

 

 

Shouldn't sweat it for a few mm. (A concrete poker would level it out pretty good). Cheap laser level is good for pegging out.

 

https://www.amazon.co.uk/Tilswall-Self-Leveling-Horizontal-Vertical-Magnetic/dp/B08LN644WG/ref=sr_1_24?dchild=1&keywords=cotron+laser&qid=1614541501&sr=8-24

 

Soon be but a distant memory when you're sitting in there! 

[daiking]

20 minutes ago, Onoff said:

 

Shouldn't sweat it for a few mm. (A concrete poker would level it out pretty good). Cheap laser level is good for pegging out.

 

https://www.amazon.co.uk/Tilswall-Self-Leveling-Horizontal-Vertical-Magnetic/dp/B08LN644WG/ref=sr_1_24?dchild=1&keywords=cotron+laser&qid=1614541501&sr=8-24

 

Soon be but a distant memory when you're sitting in there! 

 

I wouldn't know how to use one them either

[Onoff]

11 minutes ago, daiking said:

 

I wouldn't know how to use one them either

 

Even you could do it! ?

 

 

[daiking]

3 minutes ago, Onoff said:

 

Even you could do it! ?

 

 

 

This is precisely what I've tried to do with a traditional level. 

 

hit the peg, check the level, hit the peg, check the level, hit the peg, check the level, just a little bit more, (expletive deleted), too low. Pull it out and do it again, ad infinitum.

[Onoff]

Just now, daiking said:

 

This is precisely what I've tried to do with a traditional level. 

 

hit the peg, check the level, hit the peg, check the level, hit the peg, check the level, just a little bit more, (expletive deleted), too low. Pull it out and do it again, ad infinitum.

 

The laser is the constant.