Advice on base for new garden room

[LazerBen]

I am looking into putting one of these onto the house:

Addroom Modular Garden Room 4m x 3m | Extension Alternative

A leading Garden Buildings Company, we sell quality log cabins, climbing frames, garden offices, and sheds to bring your garden to life.

dunsterhouse.co.uk

I am having a hard time deciding how best to create the base for it and have a couple of questions I wonder if anyone here can help with:
1. The base needs to be level but as I understand it concrete bases should be graded to allow water to run off I believe it would be half a centimetre drop over the 3m.
2. Can I lay the concrete base up to the wall of the house?
3. If not what gap would I need and how would I manage that as a potential point of entry for water/damp into the garden room?
4. Would you recommend an alternative base to construct on top of?
5. I am also considering laying a new patio at the same time as putting down the base, would it be a good idea to just patio the entire area and build on that, dunster house suggests a "suitably consolidated base"

Any thought would be much appreciated.

Cheers

 

[Ivor Windybottom]

You could probably build something similar in brick for that sort of price or a bit more, depending on how involved you want to get.

Apologies if it offends, but that building looks crap. Reminds me of a post-war Butlins chalet. If/when you sell your house then it probably wouldn't add any value, and some buyers might want to allow for demolition costs. Plus surveyors might get all excited about "non-conventional construction", giving potential buyers a problem getting a mortgage.

I just bought some bricks for 36p each. OK, they were an end-of-line clearance price, but proper building isn't that frightening.

 

[23vc]

Why would you need water to run off it if it’s going to be covered by a building? Base should be level.
You could slab the whole area yes, as an alternative to pouring concrete, but it’s likely that area still needs to be a raised plinth compared to the surrounding ground level.

 

[LazerBen]

You could probably build something similar in brick for that sort of price or a bit more, depending on how involved you want to get.

Apologies if it offends, but that building looks crap. Reminds me of a post-war Butlins chalet. If/when you sell your house then it probably wouldn't add any value, and some buyers might want to allow for demolition costs. Plus surveyors might get all excited about "non-conventional construction", giving potential buyers a problem getting a mortgage.

I just bought some bricks for 36p each. OK, they were an end-of-line clearance price, but proper building isn't that frightening.

Yeah, but I am not a builder and wouldn't know where to start building something out of brick from scratch, let alone laying bricks in a manner that would actually look good. Plus I'd have to dig and pour footings for a brick construction wouldn't I?

 

[LazerBen]

Why would you need water to run off it if it’s going to be covered by a building? Base should be level.
You could slab the whole area yes, as an alternative to pouring concrete, but it’s likely that area still needs to be a raised plinth compared to the surrounding ground level.

Was thinking of the possibility that water around the construction would pool up and seep under the sides, once under there it would just create a super humid and damp environment.

 

[23vc]

…Hence the base for it needs to be higher than the surrounding ground

 

[LazerBen]

...indeed, makes sense

 

[mrrusty]

If you are capable of accurately building the base, you are capable of building the whole building. Have a look here for some ideas. https://www.simplysips.co.uk/what-we-can-offer/

As everyone has already said, you want the base to be higher than the surrounding ground, and you want the room to overhang the base so that water doesn't run down the walls, on to the edge of the base and under the walls in to the room.

Couple of ideas - concrete pad exactly the size of the room structure, single course of brick/block/concrete lintels (good for quickly making a concrete raised section). Frame on top, then membrane and cladding down over the edge of the raised pad with gravel drainage around the edge.

concrete pads or easypads https://easypads.co.uk/ and a timber frame base.

 

[Ivor Windybottom]

Basic bricklaying isn't that hard really, a few YouTube videos should be enough for anyone with reasonable DIY skills. You do get to practice underground first, if you make a mess of it then get a brickie in for the rest.

You could probably buy bricks and pay a brickie for similar money to these flatpack buildings.

You will need footings. Again, not terrifying and within DIY scale, probably even hand-digging at that sort of size.

 

[LazerBen]

Is there a good step by step guide anywhere for this sort of thing? Just want to see what it would take to end up with something fit for use, will last and won't let water in anyway

 

[Ivor Windybottom]

For what sort of thing?

 

[LazerBen]

For what sort of thing?

Building a conservatory/garden room from scratch as you suggested. Ground prep, foundation, damp protection brick laying, how to join to the original building etc.

 

[foxhole]

You can get adjustable legs that support the structure with no need for concrete.

 

[Ivor Windybottom]

There are loads of YouTube videos. Start watching one, a million more will appear in your homepage.

One starting point...

Treat all youtubers with some caution, I've seen these two do things that aren't best practice. Watch a load, pick and choose the best tips.

A proper building will add value to your home. I doubt that a flatpack will, and my guess is that the outlay won't be very different.

 

[LazerBen]

You can get adjustable legs that support the structure with no need for concrete.

Do you have an example?I'd be interested in seeing a video of a build using this method if you know of one.