Is Ecobrix worth the extra £££?

[Great_scot_selfbuild]

Hi All,

 

Our SE has proposed using ecobrix for our double garage walls, 2 sides of which will be designed as retaining walls and have tanking etc. The Ecobrix proposal sounds great, I spoke to the company and the integral insulation (in the non-retaining walls) sounds really positive, but then my contractor who has priced it up has the ecobrix coming in at c.£7k and he asked whether I’ve considered other options such as standard hollow concrete blocks (c.£2k). The difference in cost has given me pause for thought, but then I will be trading some of the saving for increased labour time (we’re not doing this bit ourselves), plus there will presumable need to be some additional layer for insulation / protection against condensation?

 

I don’t know what the overall cost saving may be, and whether there are other benefits for ecobrix (thermal?, acoustic?). For ecobrix, will we have to line the inside face of the wall? We’re thinking ply/osb as it’s just the garage but I’ll be wanting to fix mounts and brackets to the wall, including bike hooks.

 

Grateful for your thoughts/experience especially if you’ve used it.

 

Many thanks!

[Nickfromwales]

Hi.

 

Ecobix (used to be Durisol) are only part filled with insulation, and part filled with concrete, but the woodcrete construction is also quite porous. Tanking for subterranean conditions would need to be meticulous with that type of product imho.

 

Have you considered an EPS block such as Nudura? The XR35 gives a complete 100mm external insulation shield, is near zero water / moisture permeable, and then has a solid concrete core with a second solid layer of 100mm EPS internally. 

 

That has a nylon spine set into the block every 405mm for fixing sheet material.

[Great_scot_selfbuild]

@Nickfromwales no we haven’t considered EPS. Thanks for the response.

[JohnMo]

1 hour ago, Great_scot_selfbuild said:

ecobrix coming in at c.£7k

Have you checked the price yourself?

 

1 hour ago, Great_scot_selfbuild said:

integral insulation

Why insulation type blocks in a garage? They do thinner cheaper ones that are just concrete filled. You still have the equivalent of a 100mm wood insulation.

[nod]

It’s a crazy idea Thousands of basements are built using concrete blocks and if you want to add insulation It can be added afterwards 

Im guessing the garage is integrated 

Also id check with the tanking contractor as to how suitable Durisol is It will soak moisture like a sponge 

[Nickfromwales]

2 hours ago, nod said:

Also id check with the tanking contractor as to how suitable Durisol is It will soak moisture like a sponge 

I’m expecting that they’d have a LOT of work to do to make a woodcrete subterranean structure watertight tbh.

 

Rainwater was getting to the room interiors on 2 previous projects with woodcrete, at the very bottom of the block and at DPC, where it was literally forming a mini river across the slab. Woodcrete is entirely dependant on the external rain screen being 100% kosher and weathertight before this issue goes away.

 

It can be done, just why would you make such a rod for your own back?

 
 

EPS here is a no brainer, and sorry @nod, but better and higher performing than blocks (which are also porous?).

 

 

[Nickfromwales]

11 hours ago, Great_scot_selfbuild said:

@Nickfromwales no we haven’t considered EPS. Thanks for the response.

You’d just use that then to create the whole garage structure and swap disciplines at the dwelling, or just carry on with it. 

[ToughButterCup]

4 hours ago, nod said:

... Durisol is It will soak moisture like a sponge 

 

Yes it does. Almost

Durisol is 86% air. Unlike a sponge it dries out as fast as it gets wet. Bit like my old Landover. Water leaks out as fast as it leaks in.

 

2 hours ago, Nickfromwales said:

I’m expecting that they’d have a LOT of work to do to make a woodcrete subterranean structure watertight tbh.

...

 

I would not consider using Durisol underground: in fact it might well be useful as part of a soakaway design. 

[Nickfromwales]

Yup. Clients who built with Velox were advised by the architect and by the V rep that it was ok to have the woodcrete below DPC in a waterlogged site, and I thought it was a barking mad idea…

 

…almost as barking mad as the architect not installing insulation between the ground bearing heated raft and the soaking wet clay in his GA drawings 🤷‍♂️.
 

Queue yours truly promptly asking WTF, at the pre-construction stage, and then a miracle happens where the ‘new’ drawings have EPS, PIR and Marmox detailed in. Ffs. 🤦‍♂️ 

 

Woodcrete above ground yes, if you must eg DIY, but you’ll still not change me from EPS ICF as the best option overall; insulation better, full fill vs part fill with concrete, weathertight at the pour stage, and wonderfully airtight by default. Needs no parge coat etc, easier for 1st fix and affixing sheet material to, with these things then saving time and money downstream.

 

Most EPS ICF companies support self builders and DIY’ers, so the only downside of EPS is you have to hire bracing props in to hold it together during the pour, as there’s a LOT more concrete in those than with the pre-insulated core woodcrete blocks.