We want to build a glazed (extended summer) conservatory under our balcony. This turned out to be easier said than done . So far, the feedback from various carpenters has been disappointing. I've heard everything from the entire balcony needing to be dismantled to "how did you intend to solve (load-bearing, drainage)?" (which I foolishly thought was the reason I wanted to request quotes - I can't do this myself...). There are no threads on the topic in the forum. Is it really that desperately difficult?
Current construction:
- A post that currently supports the balcony along with the wall.
- Drainage from the balcony from sheet metal under the balcony floor (decking)
The drawing shows a simple sketch of the plan - to extend the conservatory both forward and about half a meter out on the side, in front of the brick wall.
New planned construction:
- The supporting post is replaced by a load-bearing structure (glulam beams? H-beams?)
- Polycarbonate roof
- Styrofoam as insulation under the floor
What seems to be the problem, especially, is the drainage. Half of the balcony (innermost) is under a roof, and the rain comes in only occasionally during strong winds (so far, 1 time/3 years as far as I know).
It surprises me that the carpenters sigh/have no solution for this, as about half of the identical houses in the area have built conservatories under the balcony. I have visited neighbors and looked at a few, but for me as a layman, it's impossible to assess the quality of these constructions. Is it impossible to create a conservatory under the balcony with some light insulation against ground cold?
Attached are some pictures of how it looks today, the measurements, and a very fancy sketch of how it should look.
It is probably not a carpenter you should contact, but a structural engineer who can calculate what is needed based on loads, etc. From that construction drawing, you can likely get a carpenter to do the actual construction work.
Just as a reminder: building permits with the drawings they require are also needed, of course.
It is probably not a carpenter you should contact but a structural engineer who can calculate what is needed based on loads, etc. Based on that structural drawing, you can probably get a carpenter to do the actual construction work.
Just as a reminder: building permits with the necessary drawings are also required, of course.
That seems very reasonable when you say it. The carpenters I have been in contact with have been associated with various conservatory/glazing companies that clearly market that they handle and build conservatories on a turnkey basis, so I thought they should know their stuff. Especially those that describe that they also design the documents needed for building permits, which those I have been in contact with claim to do
When it comes to conservatory/glazing companies, I guess those companies provide the carpenter with all the necessary materials for their specific solution. For building permits, the drawings aren't that advanced; it's more about the elevation drawing rather than the dimensions of the posts.
Addition: The measurement under the decking on the balcony and the metal sheet seems to be 25cm. That should mean around 15-20cm of free space if the metal sheet is removed. Maybe that is the magical key to avoid tearing down the balcony to create a lightly insulated sunroom....
If the balcony is to look as it does today and the corner post is to remain, it can hardly be a major problem. If the balcony has a waterproofing layer, ensure that water landing there is directed onto the sunroom roof. Make a metal roof for the projecting part of the sunroom; there is absolutely no advantage to having a transparent roof in that situation. Do not use the balcony to support the inner part of the sunroom roof. The load requirements for balconies are high, so the capacity available there is likely already accounted for.
If the balcony is to look like it does today and the corner post remains, there can hardly be any major problem. If the balcony has a waterproofing layer, you need to ensure that water landing there is directed onto the patio roof. Create a metal roof on the protruding part of the patio, as a transparent roof in that situation is not an advantage. Do not use the balcony to support the inner part of the patio roof. Load requirements for balconies are high, so the capacity present is likely accounted for.
No, the idea is to remove the corner post as it would otherwise end up inside the patio. So the construction of the patio must be load-bearing in two directions. The balcony does not have a waterproofing layer today; instead, the water is mainly directed down via the metal roof and during extreme weather along the walls.
A transparent (opal white) channel plastic roof is a must, as the room inside would lose a lot of daylight from the patio being built, so maximum light entry is a priority. If it didn't run away in costs, I would prefer to have a glass roof on the outermost part to let in even more light.
Then again, it's probably just something to live with that it's not the prettiest to have opal white all the way under the balcony. I'll include some pictures I've taken around the neighbors.
I'm not sure I agree with you regarding the plastic roof. It depends a bit on the direction and what is inside. The light in the sunroom always benefits from a solid roof. You need to present the construction of the balcony to be able to get opinions on the appropriate way to replace the post. It will be quite a significant point load.
I'm not sure I agree with you regarding the plastic roof. It depends a bit on the direction and what is inside. The light in the conservatory always benefits from a solid roof. You need to detail the balcony's construction to get feedback on the suitable way to replace the post. It will be quite a significant point load.
The large living room inside only has the 3 windows shown on the plan, of which 2 + the patio door end up inside the conservatory. South/southwest facing. Why would a solid roof be better?
Yes, the load will be considerable, but the balcony does have support on both sides in the wall. The neighbors seem to have a beam in the facade, one at the front, and in between, roof beams and a glued laminated beam to replace where the balcony post has been removed. The one who extended the conservatory to the side in the same way we plan to seems to have set 2 roof beams(?) to compensate for the post. Whether that is correct or not, I don't know.
Such enclosed outdoor rooms under balconies can be found in more than every other "garden" where I live now. The houses here are mostly two-story, with two apartments on the ground floor and two on the second floor. Downstairs they have a small garden plot, and on the second floor a balcony. And it mostly looks like this: The enclosed outdoor rooms have roofs made of corrugated plastic, and as I understand it, they are completely detached from the balcony structure. And it all seems to work very well (I've only lived here for just under three weeks yet).
The best option is if the beam that will replace the post extends straight out from the house facade. That way, it is least in the way. Since the balcony lacks a waterproof layer, you need to create a new waterproof roof that includes both the balcony and the conservatory. You also need insulation if the conservatory is to be usable in seasons other than summer. This becomes better and easier with an opaque roof, for example with seam roofing in metal. Using a solar diagram, you can study the actual effects before making a decision. The west sun, for example, is low
The best is if the beam that will replace the post goes straight out from the house facade. Then it is least in the way. Since the balcony lacks a waterproof layer, you must make a new tight roof that includes both the balcony and the conservatory. You also need insulation if the conservatory is to be usable in seasons other than summer. This will be better and easier with an opaque roof, e.g., with sheet metal roofing. With the help of a solar chart, you can study the actual effects before you decide. West-facing sun is, for example, low
Thanks for the responses, Justus!
When you say that the beam that is to replace the post should go straight out from the house facade, do you mean from the facade above the patio door, or do you mean the outer brick facade outside the balcony, where the conservatory is to be built? See previous pictures.
Our thought has been that a load-bearing beam is needed that starts above the patio door all the way out to the load-bearing line above the sliding doors, and that the load-bearing line, in turn, is attached to the corner post. I am attaching another amateurish sketch of this which I hope is understandable. However, note that there will be sliding doors under the front load-bearing line, so there will be no vertical support until the corner post.
Regarding the waterproofing layer—no constructions in the neighborhood seem to have a waterproof layer on the balcony, rather the conservatory appears to have a separate roof/waterproofing layer that also serves as drainage for the balcony. See a collage of 3 different such constructions. I really hope to avoid making a waterproofing layer on the balcony as it seems to involve a lot more work due to dismantling the balcony (in principle).
The insulation is set to be frost-free, i.e., summer/extended summer. However, it will not be heated and definitely not for winter use. The only thing I hope to achieve is somewhat better insulation than just wind protection and some protection against ground cold.
I agree that sheet metal roofing would have been aesthetically better for the house's exterior, however, a disaster for the room inside. I realize I wrote incorrectly—the conservatory faces southeast. That is, in summer, the morning sun is by the side of the house, shines directly under the balcony, then rises (so the conservatory/under the balcony is shaded by the balcony) and passes through during the day. The afternoon/evening sun is largely blocked by the house bodies and the hedge that borders the neighbor (now about 2.40 high, after the renovation about 1.80 high). The section of the patio closest to the house and the conservatory will be shaded from about 3 PM in the afternoon during the summertime. Perhaps we will get a bit more light when the hedge is lower, but the house bodies block the most.
Good that you are aware of the sun conditions, something many overlook. Southeast provides completely different conditions than southwest. The waterproofing layer can of course be under the balcony if the water can run right through it. The beam that supports the post should be placed just as you have drawn it. It probably needs to be on its own post at the front of the conservatory. This needs to be calculated. Depending on the balcony's suspension, the loads can be quite large. To assess this, one must know the balcony's construction in detail. Don’t rely too much on the neighbors. It's not necessarily the case that they have done everything correctly.
Good that you're keeping track of the sun conditions, something many people overlook. Southeast gives completely different conditions than southwest. The waterproofing can obviously be under the balcony if the water can run right through it. The beam that shifts the post should be placed just as you've drawn it. It probably needs to be placed on its own post at the front of the sunroom. This needs to be calculated. Depending on the balcony's suspension, it can result in quite large loads. To assess this, one needs to know the balcony's construction in detail. Don't rely too much on the neighbors. It's not necessarily the case that they've done everything correctly.
Thanks for the answers. I can imagine that many renovation enthusiasts forget to map out the light conditions, so it's a good point. However, we are the more thoughtful types and have lived here for 2-3 years, gradually considering what we want to change . A lot of plans, a lot to learn and understand.
Hopefully, we can avoid having a separate post at the front since that would mean compromising on where the sliding doors should go. The current post is more in the way than one might think, so getting it out of the radius in front of the patio door would be really nice.
The neighbors' constructions are probably of very varied quality, but the one I have the most confidence in is Neighbor A in the earlier picture, since that sunroom was built by the previous owner who was an experienced and skilled carpenter. Unfortunately, they've moved since then and can no longer be asked about the construction. However, I've now requested drawings from the board (BRF) and have also contacted a building engineer to get an idea of what a construction drawing would cost. Unfortunately, since this seems to be significantly more expensive than expected, it looks like we'll have to put plans on hold .
. So far, the feedback from various carpenters has been disappointing. I've heard everything from the entire balcony needing to be dismantled to "how did you intend to solve (load-bearing, drainage)?" 
BirgitS said:
