Boxing out ICF overhang

[magnethead]

Hi,

I need to extend and box section 300mm downwards from the current overhand that was made, I know most fixings top out at around 300mm. How would you suggest adding this maybe double layer of 150mm insulation slabs to the bottom of this overhang?

OR could you suggest a way to properly frame it out? 

Thanks

 

 

 

 

 

 

 

 

 

 

 

 

[Russell griffiths]

What for?

is it just for show?

to hide some pipes in?

does it need to be hollow or can it be solid eps ?

what you covering it in ?

 

 

[jamiehamy]

Of its just for show and no actual purpose, if probably fix 4x2 into the edge of the concrete (in an L shape) , then just coach bolt in vertical battens on the outer edge as required (to match the depth of the insulation less the osb) . Then sheath with osb or whatever and render onto it? The weight will be minimal. 

[magnethead]

@Russell griffiths thanks, it's just for show, if I didn't make this overhand 300mm lower, the window on the right at the top, would have a skinny looking render area under it that wouldnt be in proportion

 

@jamiehamy thanks very much for your suggestion ? I'll make up a frame like you suggested, I'd nearly prefer a metal frame in case the box ever sprung a leak, also one lad told me to have the same material under the thin coat render, as two different materials could cause cracks, expanding and contracting at different rates, I might try boxing out that frame with insulation.. To have the exterior rendered surface all the same.. Thanks for your suggestion 

[Russell griffiths]

I like the idea of two layers of 150mm eps all glued and screwed on. 

Then render underneath. 

 

 

On a different topic, are you happy with that reinforcement showing through the concrete. 

[magnethead]

Yeah, two 150mm layers would be ideal, I can figure out the first layers and the fixings needed, but I would NOT trust the second layer with just adhesive, and what kinda fixings are going to get through 300mm of insulation and find concrete, and maybe the steel sections in the flooring panels, which are another 40mm in??

 

I don't understand what you mean about the reinforcement, are you saying you see rebar in that picture above?  I better go back and take a closer look if so.

Edited October 19, 2019 by magnethead

[Russell griffiths]

Glue and fix first layer using 150mm fixings, countersunk into eps by 50mm

glue second layer and fix using 220mm fixings countersink accordingly. 

 

Is that a pattern on the concrete or mesh, I thought it was mesh but it could be the fuzzy pic and my poor eyes. 

[magnethead]

I'll check out what Fixings I can get, I think they go to 290mm. (It never crossed my mind to sink them into the EPS, thanks for that) , yeah the pattern is from the OSB board the lads frame those ring beams with   you had me worried for a second there LOL

Edited October 19, 2019 by magnethead

[jamiehamy]

For fixings, just use threaded rod from screwfix cut to size (you can get them in 1m lengths) . Resin bond it in to the concrete (pretty straight forward) and use decent washers /flat plate to ensure the load is spread. Counter sink the areas as Russell said. 

[magnethead]

Some Aluminium U channel bolted to the wall to hold the insulation on that side, and then threaded bar coming down from the Concrete to hold the perimeter  area, yeah, that might do the trick!

 

Thanks Lads

[Ed Davies]

For threaded rod, stainless is about twice the price but 1/3rd the thermal conductivity. 14.4 W/m·K for stainless 304 vs 40 or 50 ish for carbon steel. The heat loss difference probably isn't significant but condensation round the ends might be noticeably better.

 

https://www.engineeringtoolbox.com/thermal-conductivity-metals-d_858.html

[Nethermoor]

The way the trade would fix this is with plastic tube washer and concrete screws, this gives a thermal break and a fairly easy application compared to using resin overhead which isn't great fun.

 

250mm version of this https://www.fixfast.com/products/fastener-systems/surefast-reg-flat-roofing-fastener-system/sf-75mm-tube-washers-for-insulation

100mm version of this https://www.fixfast.com/products/fastener-systems/surefast-reg-flat-roofing-fastener-system/sf-rs-6-1-fasteners-for-concrete-and-timber-decks

 

Fixfast have an Irish branch if that is where you are from memory?  If you are struggling from them there's other sellers online.

[magnethead]

I like threads that show the outcome, so here go's....I actually bought the stainless threaded bar, and then luckily found a supplier who had 400mm concrete insulation anchors or whatever you call them. (Thanks @Nethermoor)

 

 

Then I put up some Aluminum track (secured with 150mm concrete screws)

 

 

There are some metal C-sections running through the panels, so I could use 200mm Timco screws to get into them with a washer

 

 

I put a heap of concrete fixings in around the esges above the next morning and forgot to take a picture.

 

The final job, good enough for the plaster's to take care of

 

 

I used Tec7/CT1 on the top layer, and then got my hands on some base coat adhesive to stick the final layer on , you can see a bit spilling over the edges.

 

 

Thanks everyone for your advise

 

 

Edited December 17, 2019 by magnethead