Odd question about foundations but quite relevant to this project

[Neo Cortex]

Hey forum, I am building a garden office which will be 7m x 5m. The quote my builder gave me for the foundations was £££££'s so I am looking to reduce costs.

I can handle a spade and a pick axe and have a van so considering digging the foundations myself. Yes I know it will be a lot of hard work but thats fine. I could do with the exercise anyway.

It will of course take a long time this way but time I have. If I can do 1m of foundations per week I should have them done in time for summer. For me and the timelines of the project that is OK.

My builder warned me that if the foundations are dug and left for too long that the land would cave in. He is probably right. What are your thoughts on this?

So I was thinking about potential solutions. I could prop up the two facing walls of the foundations with a bit of 12mm ply on each side and attach a bit of batton between them to keep the pressure on the two opposing faces. Then bring in my builder to finish up the concrete pouring and build. Is this a ludicrous idea or would this be OK? Can you see any potential issues with this?

Appreciate your responses...

 

[thomp1983]

Just hire a digger a couple of days before you want them filling and take a couple of days off work.

Most people can get the hang of a digger in a couple of hours if it's a straightforward dig.

Most concrete companies can deliver next day or the day after, it's normally getting the building inspector out to sign off before pouring that can be troublesome.

 

[23vc]

I assume you’re talking about a masonry walled structure? Most garden offices are timber frame to avoid issues like the one you’ve mentioned.
If you do end up doing the dig yourself, you’ll be way too emotionally attached by the end to hand over the rest of the build to someone

 

[Notch7]

Hey forum, I am building a garden office which will be 7m x 5m. The quote my builder gave me for the foundations was £££££'s so I am looking to reduce costs.

I can handle a spade and a pick axe and have a van so considering digging the foundations myself. Yes I know it will be a lot of hard work but thats fine. I could do with the exercise anyway.

It will of course take a long time this way but time I have. If I can do 1m of foundations per week I should have them done in time for summer. For me and the timelines of the project that is OK.

My builder warned me that if the foundations are dug and left for too long that the land would cave in. He is probably right. What are your thoughts on this?

So I was thinking about potential solutions. I could prop up the two facing walls of the foundations with a bit of 12mm ply on each side and attach a bit of batton between them to keep the pressure on the two opposing faces. Then bring in my builder to finish up the concrete pouring and build. Is this a ludicrous idea or would this be OK? Can you see any potential issues with this?

Appreciate your responses...

If it’s over 30sq metres internally you need building regs

 

[^woody^]

Do you need 1m foundations?

Trenches left open for long periods have the risk of collapse, also the bottoms soften and the ground swells and this makes the building settle more or settle unevenly afterwards.

Have a rethink of your cunning plan.

 

[Ivor Windybottom]

Don't even think about hand-digging, it will cripple you and is likely to collapse before you finish, assuming it will rain heavily at least once during all this time.

You'll ruin your van suspension and will probably get barred from your local tip after 2 or 3 drops.

I'm DIYing a brick shed. It needed 1m foundations. I paid a digger driver £295 all-in to dig the lot in a day, leaving a mound of soil for me next to it. I since found someone who wanted it, who was very happy to take it away. To fill it 40cm deep with concrete pumped from the street cost £1200. I could have done full fill for a bit more but had to stop there due to pipes and cables needing to go through.

A grand and a half very well spent. No doubt any "builder" would have charged a massive markup on top while doing nothing other than making a couple of phone calls.

I then built up to DPC myself - 10 brick courses. Now I don't want to hand it over so will continue with the floor and brickwork, just as soon as this wet weather clears off.

 

[23vc]

Windy - you did well to get someone to take the muck away for free, did they have a grab lorry?

 

[Koolpc]

I guess if no rear access then you wont be able to get a machine in!

 

[Notch7]

The quote my builder gave me for the foundations was £££££'s so I am looking to reduce costs

How much is ££££££ to you?

concrete + skips / muck away could be £1500 add on £500 for digger / dumper hire and you would be up to £2k. The bit you would be saving is the builders Labour + contingency + profit - have a work out how much that is

the problem with pricing groundworks for a builder is that all sorts of things can result in cost overuns, eg:

-unknown issue causes digging to be paused half way through meaning builder has to off hire plant
-skip no show causing double handling
- concrete delivery no show meaning paying lads on site to do nothing

So builders have to put on a decent margin or they easily lose money.

Maybe see if you could find a local ”man with digger” he would do it in a day. Or find a local groundswork specialist - they might give you a better price than the builder.

 

[Notch7]

I guess if no rear access then you wont be able to get a machine in!

Builders aren’t too keen on those jobs these days

nobody wants a hand dig

 

[Hugh Jaleak]

Hiring a Digger is one thing, but tip it over, or hit a service, and suddenly all that money you think you've saved will be gone, and some more after it.

 

[thomp1983]

How much is ££££££ to you?

concrete + skips / muck away could be £1500 add on £500 for digger / dumper hire and you would be up to £2k. The bit you would be saving is the builders Labour + contingency + profit - have a work out how much that is

the problem with pricing groundworks for a builder is that all sorts of things can result in cost overuns, eg:

-unknown issue causes digging to be paused half way through meaning builder has to off hire plant
-skip no show causing double handling
- concrete delivery no show meaning paying lads on site to do nothing

So builders have to put on a decent margin or they easily lose money.

Maybe see if you could find a local ”man with digger” he would do it in a day. Or find a local groundswork specialist - they might give you a better price than the builder.

I'll agree builders have to price up for unexpected costs and should be paid for anything unexpected but you never see them offering to remove those costs from the job if it all goes easily do they?

 

[^woody^]

I'll agree builders have to price up for unexpected costs and should be paid for anything unexpected but you never see them offering to remove those costs from the job if it all goes easily do they?

I've done that often on private jobs, and write it in to tender documents so that contractors do too.

 

[Neo Cortex]

I assume you’re talking about a masonry walled structure? Most garden offices are timber frame to avoid issues like the one you’ve mentioned.
If you do end up doing the dig yourself, you’ll be way too emotionally attached by the end to hand over the rest of the build to someone

Yep it will be brick built. Mainly because this is my preference, for various reasons.

 

[Neo Cortex]

If it’s over 30sq metres internally you need building regs

Yep I have paid the inspector for this. He will come around to look at the pilot hole in the next few weeks.