The Best Way to Fill a Large Inspection Pit? HELP!

[LoveTheDIY]

Hi everyone!

This is my first post and I'm really hoping somebody can help me !

We are in the process on converting our garage into a garden/office room. The garage currently has a large (2.3m long x 1m wide x 1.5m deep) inspection pit, which fills with water to about 3/4 high. Even if drained, it fills back up due to it being on the water table. Please see pics attached.

We will be laying a timber frame on the floor to raise the height and insulate, and we are concerned that if we do not fill the pit, it will cause damp in the long run.

I have had a quoted £400 for 6 tonnes of type1 to backfill the pit, but somehow this feels like we are literally throwing money (which we don't really have) down the drain!

So, my questions are:

1. Do we actually NEED to fill the pit?
2. If so, what would be the best and cheapest way to fill the pit?
3. Do we need to fill the whole thing, or is there a way to fill above where the water rises to only?

Thank you kindly for any advice!

 

[lostinthelight]

Something to consider is that if you don't completely moisture seal above the fill any wood above will rot.

 

[Mottie]

Fill it with whatever is on the other side of the pit walls.

 

[Old Salt]

Hard core plus a cement finish say 100 mm’ish

 

[scbk]

Dead bodies would be ideal

 

[scbk]

Or you could sell the pit on ebay?
Just the hole part of it, keep the bricks.

 

[freddiemercurystwin]

I'd be inclined to fill it with rubble, freely available off marketplace and then a bit of beam and block supported off the brick skin to infill the hole.

You can't expect to use hardcore and compress it and then build off that hardcore, it's likely to sink further.

 

[freddiemercurystwin]

Or instead of beam and block, a supporting concrete slab that sits on the brickwork, designed to only bear off the brick inner skin.

 

[Koolpc]

Put an advert up asking for any old hardcore / bricks....

 

[foxhole]

Had same in my concrete garage , the garage filled the pit nicely after demolition .

 

[cwhaley]

Dead bodies would be ideal

Alright Fred.

 

[RandomGrinch]

Dead bodies would be ideal

You may need a bit of quick lime first - will help in reducing the odour!