Fixing a timber post to an externally insulated wall

B

Boatless

Guest
Hi all,

I've recently had the insulation upgraded on my house by adding external insulation to the 9" cavity block walls. 65mm aeroboard type stuff, a few layers of fiberglass mesh and an acrylic render. For anyone interested, the difference is noticable.

I would now like to fit a set of double wooden doors to close off the side of the house. I figure I should hang the doors off a post on each side of the entrance.

My question is; what is the best way to fix a post to this wall? I guess the new finish wouldn't have the strength to hold a post and door, especially with the winds we get here. So I'll probably have to fix it through the insulation to the cavity wall. What type of fixings are best and what spacings should I use. Each door will be about 1.5m wide by 2m high.
 
could ye not dig a hole and concrete in a post tight to the wall without fixing it to the wall
 
I would cut out the exact size of the post with an angle grinder and fix it to the wall directly.
 
hi,
i would use a 110/150mm frame fixer or express nail. this will work no problem. drill a 8mm hole and just tap fixing in....
a fixing every 600/900mm will do.
 

Hi Boatless. We have a cavity block house and we're thinking of going the external insulation route also. You say the difference is notable. Is it very much so? Also, if you don't mind me asking, roughly how big is the outside of your house and was the job expensive?

Thanks.
 
Big hole, big lump of concrete, solid post = solid door.

The wall is cavity block, so even taking the external insulation out of the mix, it is not the most solid/strongest/easiest wall to attach anything to.
 
Drill through the insulation, into the block.
Chemically anchor a threaded bar in the block work portion of the structure.
Wind a pair of lock nuts onto the bar to sit flush with the finished render level.
Fix your post to the threaded bar and lock in position with a locknut, cut off the excess bar.
The base of the post should be concreted in place, wrap it in damp proof course to prevent the concrete rotting the post at ground level.

By stabilising the top of the post with the threaded bar you will avoid breaking the render and insulation layers. And possibly cracking the render for an area around the post.
 

What he said...
 
Boatless said:
<snip>Each door will be about 1.5m wide by 2m high.
Click to expand...

Why do you need such big doors - is this a security thing - are there others in the estate?
These are the size of garage doors - 2.6M clear width overall at a guess allowing for door thickness.
If you're hanging the doors on the house, without the benefit of a garage or shed enclosure they'll be seriously affected by the wind.

I would be concerned about the wind taking the door and; -

  • impacting a person
  • pulling out the hinges
  • impacting the wall finish

Wind speeds seem to be getting higher in the winter these past couple of winters so the concern is real.

With 1.5M widths you're getting into gate technology.
Typically this involves cross-braces and reinforcing braces near hinge points.
You are also looking at positive location in the ground and with restraint hooks for the closed and open positions respectively.
If you have young children you need to exercise foresight with such big doors, or indeed any heavy door without a closer to moderate closing speeds.

Think fingers and faces.

ONQ.
 
 
Dont dream of hanging gate post off either insulation directly or off 215 cavity block wall. ===Chartered Engineer
 
Sconhome said:
Drill through the insulation, into the block.
Chemically anchor a threaded bar in the block work portion of the structure.
Click to expand...

A cavity block is only about 25mm deep in places. Surely not enough to give you a proper fixing?
 
Thanks for all of the comments folks. Some meat to chew on. What about a steel post concreted at the base and braced at the top by fixing it to the wall and roof joists, it is a bungalow.

The gates will form the front end of a large carport where I plan on doing work on dinghies and using it as a workshop area. I note the point about the size of the gates. That is just the width of the gap, but I planned on serious gates anyway with restraints for both open and closed positions. I was also thinking of an alternative, a 2m and 1m gate, the smaller to allow the kids get bikes and the like in and out without having to move both gates.

There will be a frame above the gates to allow for securing the gates at the top as well as the bottom, so that might add extra stability to the gate posts. The frame will also support the end of the perspex roof. I suppose I'm building a garage, but I'll be the only guy on the street with a clear roof, so it will feel different )

Big smoking shed!!

Hi Mebs, As for the improvements in the insulation, I'll update you once all the bills are in. As I mentioned above, we are in a bungalow. We also brought our roof insulation somewhat above the current regs. I'll pass on the details to you and post the info in the energy section also.
 
Even anchoring the post in the ground at the bottom, and even with a restraint strap at the top, the post will be inclined to move, and this will cause your render to crack. The problem then will be that water will get in between the insulation and the external block, and you'll have damp problems.

Avoid drilling or fixing through the external wall insulation system at all, and use (even if very substantial) a steel column properly concreted into the ground, altogether. As for the general width issue - is there room on the other side for this to be a sliding gate ? Or, it could be a fan-fold door ?
 
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