Fredsboy

Advice on Stringer dimensions please. The existing replacement stringers seem to be seems 6x4” - looking at current TCV there are no hard and fasts but has one design using 50mm x 75mm x 3.7m (there are many variations and dimensions) I am happy to put in the work on multiple posts/stobs for length strength but want to ensure sufficient strength robustness in the width and depth - bearing in mind we will multi-purpose some stringers as 'new' replacements and others as sitting on the old infrastructure

analogy I guess is underpass in South London - got me thinking

Gotcha. a lot of the culvert advice seems to assume a road - we are going under a boardwalk, but assuming the same principle, maybe we should include a wee beastie tunnel higher than the water level so they can get under without going in.. Paul

Apologies Openspaceman still new to a lot of this, do you have an example "muddy grip bridged by the decking " Paul

I am thinking that we will 'bridge' the run off stream. Is there any mileage, while the walk is up, in shoring the stream with sides (of what) or even a culvert?

In a close up we can also see that an earlier walk was built in places without poles, using stobs and stringers butting up to poled sections. so a real mish mash

We went back in this week and checked another section. As the pic shows this is where the excess water in the Carr trickles back into the lower ground and main pond. It looks as though poles were laid at 90% across (actually damming) the trickle (stream after rain) and rotting the entire infrastructure

Next question: as the passing water then flows on to a fishing lake what is a safe product to treat timber with please to minimise potential toxic leaching

This is a great pic looking back over the exposed inspection. Yo can clearly see a cross section. I have gently placed a pre-cut stob to give some scale. You can also see the bed looks more like a compost pile than support for a board walk. Very rich in insect diversity! so I am now thinking.. and this is where you come in with feedback but gentle PLEASE.... I could place a series of sobs and cross- pieces in the gaps and use new 6"*4" stringers slotted in UNDER the good boards at either end, OR, drop some appropriate sized Alder and use those trunks to replace telegraph poles - BUT I don't know enough about Alder to know if it will rot too quickly; OR a combination OR another idea (please). Either ways - i am glad we did the inspection last week just pushing on with over laying would have been an expensive mistake, and as a charity, funds are VERY scarce

I dug out under newath and found the earliest substructure seemed to be trunks , not sure what but think NOT Alder as it was an ivory white and not that orange as when cut Alder is exposed to air. Too far gone to really tell. I have tried to 'draw' what I found. A bed of Timber, then at 90degrees two telegraph poles making up two stringers with oak boards at 90 degrees making the path. In some sections there are very short poles also rotten suggesting a repair.

Well that WAS the plan - before hanging all bets on that one, we opened up a collapsed section and found that perpendicular long poles used a s stringers has rotted

On Friday I went back armed with camera and crow bar. This next pic shows how a boardwalk on a board walk has been started and is the current plan to totally restore. You can see the new stringers protruding and placed on the previous boards. I'll try and use previous rather than old or original as I am not too sure of provenance

Thx openspaceman, I have access to a lot of alder there, any suggestions as to how to incorporate?. paul

Here you can see the drop where one pole has rotted the the next is still intact. Plus Teen upgrade to wheelchair kerbs - is there a proper name for the 'kerb'? PS don't take this as a Teen attack - I was one once and have engaged with the locals and asked if they want to join the repair work party - even gave them my number and no abuse suggests I got the wrong teens or they are just kids and hadn't thought through what they were doing - benefit of the doubt is the latter

The orange blobs are 16 or so places where the supporting infrastructure has collapsed. I plan to use a recip saw to get access and then dig and drop new stobs. Not sure if there is anything for the stob to bite into or if I need to place another stob opposite and add a new crossbeam - I'll find out tomorrow with a pilot/experiment