Building walkway from 1st floor into garden

[Leedschap]

Our garden rises steeply from the back from our property via a series of retaining walls / steep slopes to a terrace area at the top.  It’s about 6m height difference from the back door to the terrace. 

 

Access is a bit long winded as the only steps up are round the side of the house by the road at the front. 

 

I’d like to make access to the garden from the  house easier and try and tie the two together a bit more.

 

Im considering replacing a first floor window on the landing with a door, and building a walkway / bridge which will mean the garden can be entered at a higher level, much quicker and easier.  

My initial thought is to form a circa 0.9m wide walkway using a pair of 3m x 0.3m x 0.125m hardwood (jarrah) sleepers inserted into the outer leaf of the house, bearing on a stone foundation I will build into the slope.  Then use planked jarrah sleepers for walkway treads and adding handrails both sides.    Will need to build a couple of new steps to tie into existing garden path.
 

The look will be somewhat rustic but ties into the rest of the garden and terrace which uses similar sleepers.  
 

Would appreciate thoughts on viability of this project and whether this is likely to work!  Was hoping to avoid use of structural engineer as load seems relatively low - 3-400kg for structure plus pedestrian use?

photo of window and outdoor area here

 

Cheers

 

RD

 

 

 

[Leedschap]

Here is photo from inside of property through window which am proposing to turn into doorway. 

[Temp]

My first thought was that the span looks like it needs to be more than 3m but perhaps the photos are deceptive.

 

I think 300 x 125mm is probably overkill for 3m but I'm not a structural engineer. I'm just going by the span tables for floor joists. Three smaller beams would be easier to lift into place. 

 

Building regs won't allow just a simple hand rail. You need vertical spindles with gaps less than 100mm to discourage kids climbing. See Approved Document K.

[Nickfromwales]

Hi.

 

If the neighbours don’t kick off to planning dept etc about it, then see the following. (If there’s any chance of annoying the neighbours with it then consider a glass balustrade).
 

I would avoid penetrating the external leaf of the house as that’ll need to be made weathertight, plus it would be a cold bridge in the wall which isn’t great.

 

Instead, I’d get a steel wall plate made and fix that into the wall, with a profile that allows for a good amount of mechanical fixings to be installed. Have a tongue protruding at the bottom of it, an L section, so your timbers can fix to it, and then your foundation the other end needs to be ‘concrete solid’ to prevent any movement of the finished structure away from the house.

 

Is the length 3m? As said above, looked more like 4-5m total, eg when tucked into the foundation into the bank?

[Leedschap]

 

Photos not the best, but it’s 2.6m from the external wall to the dry stone dwarf wall you can see in 2nd pic.  So I figured 3m would allow a decent bearing both ends.  Was planning on replacing a section of the dry stone wall with a (substantial) concrete plinth, and casting in “sockets” for the sleeper ends.
 

i hadn’t thought about a steel plate but i like that idea as less intrusive and as you say removes cold bridges etc.  I’m sure I can find a fabricator to knock something up.  Only possible issue is fixing to the wall as house is built from 100mm thick hollow blocks, I’m not sure that expansion bolts / thunder bolts would be secure enough?

 

wondering if the additional load is likely to cause any issues with the window below? im assuming this has a box section type lintel like the other windows in the house.  
 

in terms of edge protection  I had in mind  full railings with spindles as would be lethal to kids otherwise!  Thankfully it is very private and invisible to neighbouring properties.

Edited 4 hours ago by Leedschap

[Nickfromwales]

1 hour ago, Leedschap said:

i hadn’t thought about a steel plate but i like that idea as less intrusive and as you say removes cold bridges etc.  I’m sure I can find a fabricator to knock something up.  Only possible issue is fixing to the wall as house is built from 100mm thick hollow blocks, I’m not sure that expansion bolts / thunder bolts would be secure enough?

You could have a 40mm 'tang' at the top of the plate, so it is a Z, and grind the top of the plate into the wall so it hangs, and then the mechanical fixings are more of a shore than a sheer connection, splitting the load between the two. I'd get that made in stainless vs galv, as I simply wouldn't want an ounce of corrosion to upset the longevity. Not a huge uplift in cost, as a steel plate would need to be fabricated and then sent away to be galvanised anyways.

 

I'd use resin anchors rather than percussion or expansion fixings, with those left to fully cure before cranking down the nuts to send it home. Beware dissimilar metals making contact, and get the holes in the plate oversized to allow nylon sleeves to be used as inserts to keep the mild threaded bar away from the mild steel; these two are not friends at all! Possibly look at using stainless threaded bar and nuts / washers, but check shear strength and suitability.

 

You could remove the render where the plate is affixed to further increase the purchase, and use a bond such as Sikaflex EBT behind the entirety of the plate to weather seal it and for further mechanical / bonded fixing. It's not a huge ask here tbh, but better safe than sorry, or better still to avoid doing it twice. 

[saveasteading]

All the above agreed.

I recall there being mesh inserts for epoxy bolting into hollow blocks. 

That would keep it all solid and even clamp a bit on the inside.

But overall I would prefer it not fixed to the wall. A simple goalpost of 2 posts and a rail, using square hollow sections, not quite touching the wall, and with a new concrete footing. 

Then the house is unaffected and movement isn't a concern.

Paint the steel in specialist coating.... grey to match or something else as a statement.

 

[Leedschap]

I was thinking of 

 

- remove render to allow better purchase / friction against block

- use hilti mesh inserts and epoxy bolt into hollow blocks 

I am wondering if off the shelf galvanised angle 200x100x10 would be adequate, though agree fabricating a z profile in stainless would be a more elegant solution.  The 200mm side would be bearing the beams.

 

I am not sure that goal posts would be suitable due to the kitchen window below (there would be a post directly in front if I am understanding correctly).

 

I may look at tripling the beams and using something a little lighter and easier to handle (larch,oak?) though durability is key, hence initial thought of jarrah.   Would also allow me to use slightly longer lengths if needed.

 

thanks for the input!

[Nickfromwales]

Use galv box-section for the walkway and composite decking boards?

 

You can have goalposts either side of the downstairs openings, just use round tube painted white to mimic downpipes and have the goal bar offset.

 

A quirky design feature could be a P-shaped platform to absorb the wider end with a planter or something sat there, if you wanted to.