Garage advice possibly concrete prefab

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Garage advice possibly concrete prefab

Post by chrisgallacher » Fri Jan 26, 2018 3:58 pm

Yep, important.


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Garage advice possibly concrete prefab

Post by 747PETE » Fri Jan 26, 2018 5:34 pm

Just my tuppence worth on this,especially regards the dpc. I will eventually be building a garage too,I have had the luxury,albeit at a price,of a rented one that was inbuilt to an office,very warm and dry.However,I now have to leave there.I may well build a wooden one.This is because a few years ago I built a wooden Summer house at the top of the garden,in a very damp area.I went to great lengths with the base.Lots of hardcore topped off with 6”” of concrete,then a quality dpc topped off with a 3” fine screed.The wooden structure was lined with mineral wool,then that panelled with pine.Regardless of the weather,even almost tropical downpours it remains lovely and dry inside.The present time finds the other car under an expensive car cover,supposed to breath...it’s almost like a swimming pool underneath with condensation.



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Garage advice possibly concrete prefab

Post by DarrylWebb » Fri Jan 26, 2018 5:46 pm

I had a pre-fab concrete job at our previous house, which I bought around 20 years ago (the garage, not the house :) )

I'll agree on the 2:1 price of brick/block : sectional concrete.

I didn't have big condensation issues, but a friend of mine about 3 miles away who had the same type of garage from the same manufacturer and supplier could run his hand down the inside wall deep in winter and have a wet hand.

I've no evidence but I could only think about the air-flow/wind-direction being an issue. His house was also in something of a hollow not far from a river. He fitted the 'optional extra' wavy infill sponge sections between the corrugated roof and straight tops of the concrete sections, and I didn't. I felt there was maybe more airflow through mine to clear the damp, while any damp in his was retained.


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Garage advice possibly concrete prefab

Post by Laters » Fri Jan 26, 2018 5:53 pm

In regard to the base on this occasion I am reusing the old garage base so no need for any extra work in that direction.
It would have been great to start with a blank sheet of paper and get the ideal garage built but I have got to make the best of the situation.

My wife wanted to go and look at the Lidget prefab buildings again after seeing the comments and photos posted in this discussion and after looking around the pent mansard and apex 90 garages it seems there is little between them except the cost. If anything the pent mansard feels bigger than the apex on a size by size basis.
On a purely looks basis my wife prefers the look of the mansard to any of the options so far.

It isnt helping that the prices they are quoting are cheaper than the brochure prices and are throwing extra's in due to the time of year sale thats currently on.


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Garage advice possibly concrete prefab

Post by drcdb15 » Fri Jan 26, 2018 6:32 pm

derekoss wrote:
Fri Jan 26, 2018 3:48 pm
Nobody has mentioned the importance of a dpc within the concrete slab. Lots of moisture will come up through a solid slab without a dpc and will be as cold as.....
The slab should go do in two layers. A 4" oversite concrete then poly dpc topped with 3" screed. Fibre reinforced helps there.
The idea of placing a precast concrete structure on top of a poured slab and hoping to seal the base is a bodge. The supplier loves it as it saves him using a measuring tape or indeed any kind of good building practice. The base should be stepped so no water running down the walls can enter.

Derek
In an ideal world, of course... but as I said before, the entire concept of a sectional building is a bodge. Even the famous 1950s pre-fabs were never intended to be permanent structures. So skipping the DPC isn't any worse a sin than holding slabs of concrete together with nuts and bolts. As for rising damp, this depends very much on the local water table and the ground slope. In my case I have a drop of nearly 2 feet from front to rear, so a dpc is fairly irrelevant. A flat slab at the bottom of the valley where all the local streams converge is a completely different proposition, so you need horses for courses. Also, as OP says, there is an original base he is able to use. One option is to use an original base as the 'hardcore' layer, break it up but leave where it is, then flatten it with finer chippings before laying a dpc and then laying a new base on top of this. This will give you a raised bed sort of structure, so you'll need a bigger slope up to the door to get the car in - might make pushing it in and out by hand more problematic, but all these factors need to be considered to find the best compromise. Damp floors can be sealed to keep the water down, and cold floors can be carpeted or cork tiled. You can even have the whole structure 'tanked' professionally in a worst case. It doesn't matter too much what 'bodge' you use, as long as it works ! And if you're that fussy about bodging the garage, perhaps it would be best to save your pennies and get a full-blown brick and tiled roof structure, to full NHBC standards.

Mind you, talking of brick garages and DPCs... true story (allegedly) told to me by my favourite builder many years ago: they did a full blown, money no object brick double garage for a customer, where there was a long driveway sloping down to the garage (lots of very rich people in Sussex :lol: ) , and of course poly DPC 2 courses above ground level. One day, daughter of the house didn't fully put the handbrake on the Range Rover (or watever large heavy luxury motor they had) and it rolled gracefully down the drive, hitting the garage full on one corner.

The entire garage upper structure slid, lubricated by the polythene, about 2 inches off vertical. Whole lot had to come down and be rebuilt, after suitable re-design. :lol:


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Garage advice possibly concrete prefab

Post by Alan SS1 » Fri Jan 26, 2018 6:57 pm

drcdb15 wrote:
Fri Jan 26, 2018 6:32 pm
[


In an ideal world, of course... but as I said before, the entire concept of a sectional building is a bodge.
you'd better not tell my folks that cos they had a 'pre-fab' built in 1983 and for ease of build/ time to get wind & water tight /insulation / comfort etc you'd be hard pressed to knock it.

their slabs were around 12 to 15 foot long full height with ribs every two feet. the house came from the builders yard and was erected in a matter of a day and a half, including a 20 x40ft garage

temporary it certainly wasn't, insulation four or more inches all around, no dodgy brickie work, dashing all done inside the 'hanger' at the builders yard. the company built loads of them in Orkney as it meant all the out-door stuff was done before getting to site, (it even meant that three years later when the decide to make the house four foot longer they just poured a new section on foundation and the crane arrived with two new extensions and then moved the end out four feet!!! :shock:

in a typical way though they took on a big contract for local council who delayed payments / longer than expected etc and company went under from cash flow :cry:


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Garage advice possibly concrete prefab

Post by drcdb15 » Fri Jan 26, 2018 7:34 pm

Alan SS1 wrote:
Fri Jan 26, 2018 6:57 pm

temporary it certainly wasn't,... three years later ... moved the end out four feet!!!
so, actually, it *was* ! :wink:


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Garage advice possibly concrete prefab

Post by Laters » Fri Mar 09, 2018 12:52 pm

As a follow up the garage is up.
First impressions were it looks tiny inside compared to how the old garage looked (it is just over 6 inches narrower). That was till I put our family everyday in there and realised its a lot bigger than it looks. As the CRV fitted with ease to walk down both sides & enough room to open the door.

Going to give the panels a while to acclimatise then going to give the walls a coat of white paint to brighten it up along with some undecided floor coating of one form or the other.

Overall the build and its install are good. It looks 1000 times better than the old garage.
Will have to see how things go with it but going to be spending some time in there as my se6 should be arriving sometime late Monday or early Tuesday.


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Garage advice possibly concrete prefab

Post by Darren C » Fri Mar 09, 2018 4:27 pm

derekoss wrote:
Thu Jan 25, 2018 9:58 pm
Use SIPs Structural insulated panels. Basically two panels of wood or metal bonded to insulation. Gives you insulation and structure in one !

Plenty around down your way. Seconds & co good place to start but lots of options on fleabay. Can use the same for a mono pitched roof with a rubber cover.

You can paint or clad the outside as you like when you like as budget allows. You'll heat the place with a 1 bar electric fire.

I've managed to pick up walkin fridges of good size. When the fridge equipment is knackered the box can be had quite cheap. A Stanley knife and an allen key to dismantle in about two hours for a garage size. Last one I got was 20x20. 6" thick walls and 8" thick roof. Built a wooden structure on top and sheeted with Onduline. Cost me about a grand all in !

Derek
+ 1 :goodpost:

New Metal clad kingspan meets fire regs
Comes in any colour you want (green outside, white inside etc) no painting or upkeep.
Insulation rating is epic no condensation. Switching on a tube light will result in you breaking out in a sweat & stripping off (Drive a car in one day and it'll be still roasting in there the following day from the engine heat!)
New Kingspan works out around £70 m2 (less doors & windows) installed


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