ᐅ Building a Garage Yourself – Materials and Cost List, Does This Look Correct?

Created on: 14 Mar 2021 14:15

Hello everyone,

Originally, we planned to build a carport, but the idea of constructing a garage ourselves never completely disappeared. We have a building permit / planning permission, but it was originally issued for a timber frame garage. Accordingly, the structural calculations are available for that.

To make a final decision, I roughly compiled a list of materials and prices to estimate the costs. A master mason friend is available to help. Most prices were based on online listings or existing quotes from the current building. Only for the garage door do we have concrete offers.

What do you think? Is something major missing or are our prices completely off?

Garage made of 24 cm (9.5 inches) Ytong blocks, 7.00 x 6.50 m (23 x 21 feet), shed roof with 40 cm (16 inches) sandwich panels, sectional door, floor slab existing, no earthworks necessary:

24 cm (9.5 inches) Ytong blocks: 2,000 EUR
Adhesive, 15 bags: 240 EUR
Ring beam with reinforcement: 2,000 EUR (this is where I’m most uncertain)
Roof rafters 8 x 20 cm (3 x 8 inches), 1 m (3 ft) spacing: 500 EUR
Sandwich panels with 40 cm (16 inches) insulation: 1,500 EUR (possibly extra costs for higher insulation)
Sectional door including installation: 3,200 EUR (promotional door 2,500 EUR)
Gutter sheet metal: 170 EUR
Rain gutter: 120 EUR
Structural engineering adjustment: 500 EUR
Exterior plaster: 500 EUR
---------------------------------------------
Total: 10,730 EUR

There would also be a potential extra cost for a cement screed (45 m² x 25 EUR): 1,125 EUR. I will do the electrical work myself.

How realistic do you find this estimate?

Nemesis17 Mar 2021 12:10

#13

I am facing exactly the same situation and have a similar cost estimate. However, we are actually using the 17.5 cm (7 inch) blocks because of the greater internal width.

I have the following questions:

- From which supplier are you getting the gate, including installation? Or is the installation carried out by a third party?
- We were advised to have a rafter spacing of about 70 cm (28 inches) due to structural requirements. Is the 100 cm (39 inches) spacing in your case based on structural calculations or just a suggestion?
- Can you and/or others provide more information about the advantages and disadvantages of these sandwich panels? We also want a flat or slightly sloped shed roof and have already considered several roof constructions without feeling completely certain...

Thanks and best regards

11ant17 Mar 2021 14:19

#14

Nemesis schrieb:

I am facing exactly the same situation [...]
- Could you and/or others tell me more about the advantages and disadvantages of these sandwich panels? We also want a flat or slightly sloped shed roof and have already considered several options for the roof construction.

Have you already presented the project (sorry, I just forgot your previous username, where would I have to look in the history)?
Advantage of sandwich panels: sturdy and as lightweight as possible, with insulation that prevents the dripping issues common in metal garages without fleece. Disadvantage of sandwich panels: standard in commercial industrial buildings, meaning the price level is not consumer-oriented.

https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/

Nemesis17 Mar 2021 14:50

#15

11ant schrieb:

I just forgot your previous username

What happened that your photographic memory let you down? 😳;)
I had presented it back then, but only the house; a carport was still planned at that time, though over time we changed to a garage.
In other words, as is the case with the original poster here, the foundation slab is already in place, the structural engineering is done, the mason is ready, but the roof design has not yet been finalized, hence the question. At least it sounds very interesting. Also, after (admittedly brief) research, I don’t find the prices that overpriced...

11ant17 Mar 2021 15:08

#16

Nemesis schrieb:

What happened that your eidetic memory failed you?

It only glitches on certain days. Menopause 🙂

Nemesis schrieb:

Besides, after (admittedly brief) research, I don’t find the prices that overpriced...

I’ve never tried it myself, but firstly, professional-grade products available to consumers are typically not fast movers and usually have markups on request, and secondly, @superzapp has already pointed out that this mainly applies to the peripheral stuff.

https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/

Simon-18917 Mar 2021 15:19

#17

Nemesis schrieb:

- We were advised to space the rafters about 70cm (28 inches) apart due to structural reasons. Are your 100cm (40 inches) based on structural calculations or just an estimate?
- Can you and/or others share more about the pros and cons of these sandwich panels? We also want a flat or slight shed roof and have considered several roof build-up options but aren’t quite sure yet...

As @11ant points out, sandwich panels are commonly used in industrial hall construction. Essentially insulation (foam) with steel sheets coated in either 0.6mm to 0.75mm (approx. 0.02 to 0.03 inches) profiled steel on either side, depending on the manufacturer. The interior side is standardly always RAL 9002 grey-white with a lightly profiled surface (almost any finish is possible for an additional cost). For roof panels, the exterior features 38mm (1.5 inches) deep ribs. A very important note for roof panels: observe the minimum roof pitch (usually 3° if there are no roof openings, varying by manufacturer), use the correct self-drilling screws with sealing washers, and if possible fasten them in the ribs since they are not the water-bearing surface. On the exterior side, many manufacturers offer a wide range of standard RAL colors. A classic choice is RAL 8012 reddish-brown. Manufacturers that come to mind are Hoesch, Arcelor, Roma, Lattonedil, Romakowski.

Was the roof build-up explicitly detailed in your building permit / planning permission? Sandwich panels would also be my preferred solution for a garage roof but are prohibited by the zoning plan.

Personally, I would not recommend using so many wooden rafters but rather galvanized steel profiles as supports. Attach an angle bracket along the ridge and eaves (minimum bearing width 60mm (2.4 inches) for the sandwich panels), add two I-beams (IPE profiles) at the one-third points along the span in the direction of roof slope (design by a structural engineer), and increase the core thickness of the sandwich panel to 60mm or 80mm (2.4 or 3.1 inches) to allow longer spans with little extra cost due to foam insulation. The overall cost would likely be similar, but you’ll have long-term peace of mind.

That’s basically the kind of setup I would propose as a steel construction draftsman 😉

11ant17 Mar 2021 15:28

#18

Simon-189 schrieb:

Sandwich panels would also be my preferred choice for the garage roof, but they are not permitted according to the building plan / planning permission.

Is it because, in small quantities, they are not available in roof tile colors?

https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/

ᐅ Building a Garage Yourself – Materials and Cost List, Does This Look Correct?

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