Best practices for fixing to external wall with insulation

[Marticus100]

Hi guys,

Feels like i have a ton of questions right now

I have a new home which is externally insulated 100mm+ of polistyrene and then rendered.

I will need to drill holes for fitting external lighting, sensors, etc and a possible satelite dish (would rather avoid this)...

I have done a search but information seems a little hard to come by, has anyone had experience with dealing with this?

 

[AronSearle]

I dont actually know, But i am guessing big screws pulling whatever you want to hold up tight to the rendar, you may need a backing plate to spread that load over the face of the rendar to avoid "denting".

Is the wall timber frame or masonary, you will need to think about where and what you are screwing through and into.

 

[freddiemercurystwin]

Yes as above, long fixings into the structure with spacers or consideration give to the fixings to ensure they do not tighten up against the render, which will just crack. this may be an interesting article: https://hardhouseblog.wordpress.com/tag/external-wall-insulation/

 

[Marticus100]

Thanks guys.

It's a masonary wall so i don't need to be worried about finding studs etc.

I will have a read through that link now thanks!

One of my concernes was with water ingreess and damproofing, any ideas if silicon sealand into the holes and around the backing plate would be sufficient?

Edit:

it seems that article covers everything.

thanks again!

 

[nebjamin]

I have just had my place (in UK) externally insulated. I came across these guys while considering similar issues...

http://www.retrofitsatellites.co.uk/

(No affiliation)

 

[ban-all-sheds]

Having spoken to EWI installers about this, the thing to do is to fix pieces of pressure treated timber to the walls where you want lights, dishes etc, which match the thickness of the insulation.

The insulation is fitted around the bits of wood (which have a good enough u-value to not really compromise the overall performance of the insulation), and then the mesh and render goes over the whole lot.

 

[Marticus100]

Yeah i've seen it done that way, but the house is already fully rendered and insulated, will just have to use a wide backing plate to spread the load and hope for the best i guess.

Really don't want to be cutting chunks of insulation and rendering off the wall now.

I have just had my place (in UK) externally insulated. I came across these guys while considering similar issues...

http://www.retrofitsatellites.co.uk/

(No affiliation)

thanks good link

 

[D4N1EL]

Hi,
I have had my home done with external wall insulation and pebble dash, it is done exactly how ban-all-sheds described. Bolt a piece of wood to the wall, pebble dash/render over it then mount your stuff to the wood. I wouldn't know what is the best way to go about fitting things to the wall after the work has been done, but personally I wouldn't chance damaging it

 

[ban-all-sheds]

But if you've bought a house with EWI already installed, or you had it installed without proper planning, then what?