Insulated Raft DIY?

[LA3222]

The more I ponder it, the more I am inclined to do my foundations myself - minus the concrete pour.

 

It seems to me to be no harder than following a set of IKEA flat pack instructions - am I missing something fundamental? 

 

I have the impression that a few forum members have managed to do it themselves so I can too - at least that's where I'm heading unless someone pulls me back from the precipice with words of wisdom?

 

Sooo....what I'm getting at, is can the foundations be a DIY task?

 

TIA

[MikeSharp01]

Yes but there are catches. We did our garden room as a passive slab to experiment for the house slab. I laid the type 1 and pea shingleI, I made up the EPS elements in line with a design.I had seen some where and we poured the concrete and polished it. For the house we did almost the same but this time we needed the structural design and to get that we purchased the design and slab EPS components. We then laid the type 1 the pea shingle, put down the EPS former, installed the dampmproof membrian, the mesh, the UFH and poured the concrete.

[willbish]

6 hours ago, LA3222 said:

what I'm getting at, is can the foundations be a DIY task?

 

Yes definitely. Laying down the EPS raft is the easy bit though and comes at the end of a lot of ground work and preparation.

 

The trickiest bits I found were the setting out and making sure soil pipes and utilities were coming up through the raft in exactly the right place.

 

Are you considering constructing your own EPS raft like @Triassic or purchasing in kit form Isoquick etc?

There is a financial saving to be made constructing your own but for me it was a just another unknown and added risk. I would certainly do it that way next time.

[Conor]

I fully intend on installing my own Kore raft. And I'll be doing the pour as well... Self compacting concrete. Very little shovelling, moving, floating or tampering to do. It behaves more like a screed. Look up some videos. I think I will talk the concrete guy into being there tho...

 

Cost wise, self compacting is £80/m³ vs £60/m³ for standard c35. But a lot cheaper then me getting a crew in for a day.

 

[Russell griffiths]

@Conor can you tell me who you are getting your self compacting concrete from, I’m looking at doing my floor slab in it in stead of liquid screed. 

[Russell griffiths]

A few things you could do to remove some agro

employ a structural engineer to design it

employ a surveyor to set out the slab and all pipe penetrations

you will need another man, not wife, to help you move all the steel and tie it up

if you put a few of these things in place it should be straight forward, if you try to do everything yourself you might feel a bit overwhelmed 

[Conor]

16 minutes ago, Russell griffiths said:

@Conor can you tell me who you are getting your self compacting concrete from, I’m looking at doing my floor slab in it in stead of liquid screed. 

 

Sorry, a local company here in NI, CES quarry products.. I know our concrete and quarry material costs are a fair bit cheaper here than in GB.

 

10 minutes ago, Russell griffiths said:

A few things you could do to remove some agro

employ a structural engineer to design it

employ a surveyor to set out the slab and all pipe penetrations

you will need another man, not wife, to help you move all the steel and tie it up

if you put a few of these things in place it should be straight forward, if you try to do everything yourself you might feel a bit overwhelmed 

 

Yeah, Kore will be doing structural design, definelty required if you're doing something other than a pure timber construction.

 

I see base prep being key... I think I'll be retaining my ground works company to help with this.

 

You're right about setting out.... Surveyor for setting out all corners is key. Luckily for me that's my background.

[Russell griffiths]

I have mentioned this before so I probably sound like a broken record, my surveyor came to site 3 times to set out and it cost under £400 no brainier not worth spending your time on it. 

[Conor]

3 minutes ago, Russell griffiths said:

I have mentioned this before so I probably sound like a broken record, my surveyor came to site 3 times to set out and it cost under £400 no brainier not worth spending your time on it. 

That's good value. We would have charged £225 per half day on site.

[LA3222]

@MikeSharp01, @willbish, @Conor, @Russell griffiths, thanks for the feedback - you've all confirmed in my mind that there is no reason not to tackle this myself.

 

I have Tanners doing the structural design and intend to purchase from Kore. Getting the corners and slab penetration professionally set out seems the sensible choice.  I think I will get some help in to shift the aggregate about and for the concrete pour.

 

The slab pour is the only step I'm not keen to tackle - the pour should be easy enough, it's the finish that needs to be bang on so I will probably look to get someone who knows their onions in!!

[nod]

Setting out is Something that you can do yourself 

I set ours out with my Hilti laser 

But borrowed an EDM from a friend to double check 

[jamieled]

Commenting here as someone who didn't do it himself. Our concrete went off faster than I've ever experienced before. In that respect I was pretty happy we had an experienced concrete crew. Your idea of getting folk in to help with that is a good one and I'd probably do that again myself (not that I'll need to for a while!).