Preliminary information:
City villa (built in 2019)
36.5 cm Poroton blocks without insulation, finished with silicone resin plaster
Garage (added later as self-build)
6.50 m * 9 m (21 ft 4 in * 29 ft 6 in)
24.5 cm Poroton blocks
1 interior wall with 11.5 cm Poroton blocks (4.5 inches)
Wood flat roof
Access to the house
The concrete slab will be poured for both structures together by the general contractor.
A sketch showing the garage’s position relative to the house is attached.
When planning to add the garage later, we initially considered building it with four separate walls.
However, we were recently advised to attach the garage directly to the house without a separating wall.
I actually prefer this option because it would give us about 25 cm (10 inches) more interior space.
Now to my question:
Where and how is the roof attached or supported on the house side?
Will the ridge beam (purlin) be omitted and the rafters fixed to the masonry using joist hangers?
Is that sufficient to carry the load?
Or is it possible to create recesses in the house’s masonry to install internal joist hangers so the rafters rest inside the house wall? (But there would have to be quite a few of them, which probably wouldn’t look good before building the garage, I assume.)
What other options are there?
I can’t just screw a ridge beam to the house wall with bolts the thickness of reinforced concrete, can I?
Yes, we will also discuss this with an architect and general contractor, but I prefer to go into such conversations with some prior knowledge so I don’t get sold a pig in a poke.
Thanks for your input.
City villa (built in 2019)
36.5 cm Poroton blocks without insulation, finished with silicone resin plaster
Garage (added later as self-build)
6.50 m * 9 m (21 ft 4 in * 29 ft 6 in)
24.5 cm Poroton blocks
1 interior wall with 11.5 cm Poroton blocks (4.5 inches)
Wood flat roof
Access to the house
The concrete slab will be poured for both structures together by the general contractor.
A sketch showing the garage’s position relative to the house is attached.
When planning to add the garage later, we initially considered building it with four separate walls.
However, we were recently advised to attach the garage directly to the house without a separating wall.
I actually prefer this option because it would give us about 25 cm (10 inches) more interior space.
Now to my question:
Where and how is the roof attached or supported on the house side?
Will the ridge beam (purlin) be omitted and the rafters fixed to the masonry using joist hangers?
Is that sufficient to carry the load?
Or is it possible to create recesses in the house’s masonry to install internal joist hangers so the rafters rest inside the house wall? (But there would have to be quite a few of them, which probably wouldn’t look good before building the garage, I assume.)
What other options are there?
I can’t just screw a ridge beam to the house wall with bolts the thickness of reinforced concrete, can I?
Yes, we will also discuss this with an architect and general contractor, but I prefer to go into such conversations with some prior knowledge so I don’t get sold a pig in a poke.
Thanks for your input.
B
ballerburg132 Jan 2019 10:37Hello,
I’m interested to hear what has become of your project by now.
I am facing a very similar undertaking, but I also have to cast the slab myself, and the house is already completed. (Also 36.5cm (14.4 inches) aerated concrete block plus exterior plaster, without external thermal insulation composite system / ETICS)
No joist hangers or similar connectors were embedded. The house itself is finished and fully enclosed. Only the secondary entrance door has been installed, which will later provide access to the garage.
I was also advised by experienced friends and acquaintances to at least involve a structural engineer.
One idea that was suggested to me (in addition to the ones already mentioned here) is to span the area of about 7 meters (23 feet), where the fourth wall should be, with a steel beam. This would eliminate the need for intermediate supports while still allowing for a continuous, four-sided ring beam.
However, I was made aware that steel beams can be relatively expensive.
So, the final decision has not yet been made on my side either.
Another issue is the passageway to the house.
The current secondary entrance door, installed by the general contractor, will definitely stay in place for now. It has to remain for the upcoming blower door test.
However, I was told that I would need a fire-resistant (FR) door if I want to connect the living space and the garage.
FR doors apparently cannot be sealed tightly enough to pass a blower door test. Perhaps I will have to build the fourth garage wall with the same exterior plaster as the house and then fit an FR door into the garage wall. Having two doors immediately behind each other would of course be inconvenient. Does anyone have any ideas?
I’m interested to hear what has become of your project by now.
I am facing a very similar undertaking, but I also have to cast the slab myself, and the house is already completed. (Also 36.5cm (14.4 inches) aerated concrete block plus exterior plaster, without external thermal insulation composite system / ETICS)
No joist hangers or similar connectors were embedded. The house itself is finished and fully enclosed. Only the secondary entrance door has been installed, which will later provide access to the garage.
I was also advised by experienced friends and acquaintances to at least involve a structural engineer.
One idea that was suggested to me (in addition to the ones already mentioned here) is to span the area of about 7 meters (23 feet), where the fourth wall should be, with a steel beam. This would eliminate the need for intermediate supports while still allowing for a continuous, four-sided ring beam.
However, I was made aware that steel beams can be relatively expensive.
So, the final decision has not yet been made on my side either.
Another issue is the passageway to the house.
The current secondary entrance door, installed by the general contractor, will definitely stay in place for now. It has to remain for the upcoming blower door test.
However, I was told that I would need a fire-resistant (FR) door if I want to connect the living space and the garage.
FR doors apparently cannot be sealed tightly enough to pass a blower door test. Perhaps I will have to build the fourth garage wall with the same exterior plaster as the house and then fit an FR door into the garage wall. Having two doors immediately behind each other would of course be inconvenient. Does anyone have any ideas?
ballerburg13 schrieb:
However, prefab house doors are apparently not airtight enough to pass a blower door test.Apart from the fact that they are not designed for this pointless test anyway: why exactly should a prefab house door be impossible to make gas-tight or smoke-tight? – I consider that to be a myth.https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
ballerburg13 schrieb:
hello,
I’m curious about how your project has progressed since then.
[...]
Does anyone have any ideas here?Hi Ballerburg,
It’s been a while since I last visited this forum. I hope it’s not too late for you.
I haven’t completely finished my garage yet, but I would still like to share the current execution with you (and others who are searching).
Our design has been adjusted slightly regarding the structural engineering. The original plan was to build the garage with an open partition wall that is not connected to the house, so it stands freely.
Currently, it has developed as follows (see attached sketch):
The front wall now has a reinforced concrete column at the house wall. The back wall also has a reinforced concrete column as a connection to the house wall. The partition wall will now have a somewhat narrower opening than initially planned (1.30m (4.3 ft) reduced to 1.00 meter (3.3 ft)) but will include a masonry pillar and a lintel above the door. The entire structure will be finished at the top with a ring beam of at least 15.5 x 20 cm (6 x 8 inches). The rafters (12 x 24 cm (5 x 9.5 inches)) will be laid lengthwise over the garage, resting on the reinforced concrete column, masonry pillar, and rear wall along the house. This means the longest span to be bridged is about 6.30 meters (20.7 ft).
Contrary to the initial open plan mentioned in the first post, the walls will be 17.5 cm (7 inches) thick masonry walls all around, including inside.
The rafters are planned to connect with a scarf joint on the partition wall; however, I will likely use continuous rafters to avoid this weak point.
When the foundation slab was poured, reinforcement steel for the rebar cages was already embedded at the two support locations, but you can also add this later. For the supports, I also pre-installed steel angles in preparation for the upcoming ring beam to ensure a load-bearing connection between the beam and the supports.
E
Eberhardt17 Dec 2020 11:06Patkia schrieb:
Preliminary information:
City villa (built in 2019)
36.5cm (14.4 inches) Poroton without insulation, finished with silicone resin plaster
Garage (added later as a self-build project)
6.50m (21.3 feet) * 9m (29.5 feet)
24.5cm (9.6 inches) Poroton
1 interior wall 11.5cm (4.5 inches) Poroton
Wood flat roof
Access to the house
The foundation slab will be made directly for both structures by the general contractor.
A sketch showing the garage location relative to the house is attached.
When we planned to add the garage later, we initially thought of building all four walls separately.
Now, we have been advised to build the garage without a separate wall next to the house.
I actually prefer this option, since it would give us about 25cm (10 inches) more interior space.
This leads me to the question that’s been on my mind:
Where and how is the roof attached or supported on the house side?
Is the purlin omitted and the rafters fastened to the masonry with metal joist hangers?
Is that sufficient to carry the load?
Or is it possible to create recesses in the house wall bricks to insert internal joist hangers so that the rafters rest directly in the house wall? (That would require quite a few, and I guess the wall wouldn’t look great before the garage is built.)
What other options are there?
I assume I can’t simply screw a purlin to the house wall with “arm-thick” bolts?
Yes, we will also discuss this with the architect and general contractor, but I prefer to enter such a conversation with some prior knowledge so I’m not sold a pig in a poke.
Thanks for your information. Hello Patkia, this post is a bit older, but I just wanted to ask how you decided or how you ended up building your garage.
Eberhardt schrieb:
Hello Patkia, the post is a bit older, but I just wanted to ask how you decided or how you solved your garage situation.Hello Eberhardt,the garage is now almost finished (except for the garage door, which has an incredibly long delivery time).
What would you like to know?
E
Eberhardt17 Dec 2020 11:32Patkia schrieb:
Hello Eberhardt,
the garage is now almost finished (except for the garage door, which has an incredibly long delivery time).
What would you like to know?Sorry, I didn’t see your last post where you already described how it turned out for you in the end.
“The walls are, contrary to the original plan in the first post, all around and inside 17.5cm (7 inches) walls.”
Do I understand correctly that the 17.5cm (7 inches) Poroton blocks were structurally sufficient, but that you still needed the reinforced concrete column and the masonry pillar, etc.?
So now you don’t have a wall between the house and the garage?
I also have a new build with 36.5cm (14 inches) Poroton blocks without insulation, and the garage is planned to be about 5.6m (18 feet) wide by about 9m (30 feet) long, so I need every centimeter in width and I also wanted to build without a wall to the house...
The garage slab was built separately from the house slab, right?
Do you happen to have a photo of the garage from the front showing how it is attached to the house?
Thanks a lot,
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