could you build a frame that will give a slope to
this area? that would move water off the top
where it otherwise would sit & leak.

whatever type of cover/roof you do for this
area would need to be properly flashed
to wall so that water doesn't enter at that area.

it is hard to visualize..can you post a couple
of pics?

best of luck. like your posting title.

The problem with building what you suggest is that there is a deck at the back (just built before we bought the house) that abuts the bathroom, covering over the 2 extra feet. I talked to the neighbour (we are a semi and share the back porch/crawl space with them.) They noticed too that they have extra space below that is not above. I think the guys building this must have nipped down to the bar that used to be on the corner on their lunch break...

I'll try and post a photo to help with the visualization.

Thanks for your suggestion!

Any sign that the space might have once been used for an outside entry to the basement?

You will probably have to take up some of the decking to do anything to cover the area properly...even if it is only to fix some sort of 'tray' to divert the water into the yard before it gets to the open space.

That is an interesting question columbusguy. We have pulled up all the old kitchen flooring and there is a shadow of where the old cabinets used to be. They blocked the current basement doorway, and this confused me - how did they get into the basement?

Maybe there was an alternate access somewhere else, and the crawl space might be a clue. Although, why would you want to crawl into a cellar?

The neighbour has the exact same set up but they can't access the inside of their house from the crawl space. Ours had plumbing and heating pipes put through the wall, so they busted out a portion of the stone foundation.

Maybe it is related to the chimney that runs through the crawl space on the wall where the original exterior of the house meets up with the crawl space?

So the mystery remains....

If there is a chimney there, perhaps there is/was an access door to remove ash? Perhaps a coal storage area? I must admit it is pretty odd. :)

I had an insulation guy out to give a quote on foaming the crawl space. It was the day after a rain storm. The exterior wall was dripping wet and it had wicked quite far along the joists and into the bathroom. He said the open roof set up had to be fixed before we can insulate or it would just trap the moisture and cause more rot.

Enter the city's chief building official. His recommendation is to create a concrete cap for that opening and get it really waterproof.

Maybe then cover it with a waterproof membrane?

Should know if a few days what path we are going to take.

Rather than concrete, you could build a cap out of wood, then use the membrane--just make sure it is properly flashed.

Turns out we needed to put in new footings and a beam to support the unsupported exterior wall of the addition. A cap is being poured tomorrow. Here's hoping that all will go well and the pipes don't freeze from being out in the open now that winter has arrived in Ontario.

I am a bit fed up with the whole reno at this point. Now I am down with the flu...so won't be able to work or supervise the ongoing project...sigh...wish we had never bought this property at this point.