ᐅ Garage 8m x 7.5m, gable roof, strip foundation, exterior plastering costs

Good evening everyone,
we need a rough cost estimate for building our garage.

8m x 7.5m (26 ft x 25 ft) with 24cm (9.5 inch) Poroton masonry.
4m (13 ft) of it will share a wall with the house.
2 garage doors
2 windows
1 door to the garden
1 door to the house
Strip foundation
20cm (8 inch) concrete slab
Gable roof
Exterior plaster/render

We want to exclude interior finishing and floor covering for now.

We will do the masonry ourselves. The roof would be built at the same time as the house roof... I think that would be more cost-effective. The same goes for the foundation, concrete slab, and exterior plaster/render.

We are unsure whether we should build the house first and then the garage or both at the same time.
Opinions around me vary widely on this.

I hope you can give me a rough guideline for the costs based on your experience.

Thanks in advance for your thoughts.

Best regards,
Waldemar

wowa789 schrieb:
built with 24cm (9.5 inch) Poroton blocks.
4m (13 feet) of that is shared between the garage and the house.

I find it unlikely that there is a single-layer common wall between the house and garage in times of energy efficiency regulations. Porous bricks and 24cm (9.5 inch) thickness = double “why”?

---

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

The house will be built with 36.5cm (14.4 inches) thick walls. The separation between the house and the garage will therefore be thicker. Possibly, the garage could be directly built with 36cm (14 inches) walls as well.

I don’t quite understand what is meant by "I don’t think a single-layer common wall between house and garage complies with energy saving regulations nowadays."

wowa789 schrieb:
The house is built with 36.5 cm (14 inches) masonry. So the separation between house and garage is thicker. Possibly, the garage could be built directly with 36 cm (14 inches) masonry as well.

If it is a single-layer wall, then from a thermal perspective, I don’t see any real separation. Building the garage wall with the same thickness as the living space walls does not help. There should be at least a joint between them, preferably with insulation, so the garage has its own separate masonry leaf along the "shared" wall. Usually, 17.5 cm (7 inches) is sufficient for this, and in aerated concrete or lightweight aggregate blocks, 15 cm (6 inches) might also work.

wowa789 schrieb:
I don’t quite understand what is meant by "In times of the Energy Saving Ordinance, I rather don’t believe in a single-layer party wall between house and garage."

A garage that from the side facing the house effectively has no wall because of being made as a single masonry leaf over 4 m (13 feet) wall length contradicts compliance with the applicable Energy Saving Ordinance.

Of course, I assume the garage is unheated.

---

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

Let's put energy saving regulations aside for now.

What do the costs look like roughly?

@11ant I think you are on the wrong track. If I understand correctly, the house has already been built with 36cm (14 inches) bricks, so it complies with the energy-saving regulations. Now, only an unheated garage outside the thermal envelope is being added. The type of brick used for that shouldn’t really matter.