Well, since i havent found a "guide" with this information yet and since there is only one dead thread about it in the steam forum of F4, i thought i will just make this one to share the information i have found on the internet so far about the limited settlement size.

Ok, while i'm totally aware of the several mods on the nexus which provide a solution for this problem, those are still mods and with the next patch, you will have to wait for them to update as well as the mods so far are only for PC.
This exploit on the other hand will probably work even after the next patch and as far as my experience with Beth games goes, will work in the years to come.

Well then, here is how you exploit the size limit on all 3 plattforms(i tested it a lot on PC, works great),
thanks to SegmentedMoss from reddit to point it out:
Source: https://www.reddit.com/r/fo4/comments/3t1qzh/psa_there_is_a_method_for_eliminating_the_max/

Originally posted by SegmentedMoss:

So, I'm not sure if there is a post about this already on this reddit. If there is, I couldn't find it when searching.

Anyways, I'm sure a lot of people are starting to notice the pesky "Size" indicator when building your new huge settlements. I myself was capped out for Red Rocket gas station after building a huge house on the gas station roof. I didn't want to break down my new structure so I could build shops, but I was out of options, given the size cap.

Luckily, there is a way to subvert this size cap:

1 - place any number of weapons into your workbench inventory at the location you are planning to reduce the size of.

2 - Take those guns and put them back into your character inventory.

3 - Enter your inventory and drop all the guns you're using for this.

4 - Enter workshop mode.

5 - Hover over a gun and tap "Store" ("B" on XBone or "O" on PS4), and the gun will automatically go back to the workshop inventory. When this happens, you should notice that the size meter in the top right of workshop mode will decrease slightly.

6 - Repeat step 5 for all guns you dropped until the size bar is empty. You can use the same guns to do this over and over again.

This lets you build massive structures and settlements to your hearts content. Sorry is this is already well known, but figured spreading the word might help, as I've noticed a lot of people complaining about the build limits.

Shiggity Whomp found out that it works with all Junk items as well, thanks for that:

Originally posted by Shiggity Whomp:

It can be done with any junk object aswell. Tested on a maxed out red rocket.

If you can't quite figure it out from the description, MrBossFTW made a video about it:

I hope this helps a few people to make your designs work better with the badly designed building system we got in F4.

greetz
Joshua