Building a flying castle pre-epic [Archive] - Giant in the Playground Forums

Qwertystop

2011-06-06, 07:43 PM

One of my favorite scenes in fantasy is the flying castle/city/continent. However all of the fly abilities are temporary and only work on creatures.

One possibility I noticed was making a flat boardwalk out of permanent walls of force and then building whatever you like on top of it. It would be expensive but possible; anyone know of a better or cooler way to do it?

A possibly cheaper way would be as follows:
1: Cast Wall of Stone on the ground, forming a flat surface. You will need to cast it in such a way that the surface created exists on the Material and Ethereal planes at the same time. One way to do that is by having a manifesting Ghost cast it. If you do not want the surface to be visible, dig a hole and put it on the bottom, then fill it up.
2: On the Ethereal Plane, cast several more Walls of Stone, extending a pillar from the surface. The first Wall gives you a surface in the Ethereal to put the new ones on. These new walls should be Ethereal-only.
3: Once you have gotten the pillar as high as you want it, use Wall of Stone to make the floor of the castle, again in both the Material and Ethereal Planes.
4: Build the rest of the castle.

The support is invisible to anyone on the Material Plane who does not have a way to see the Ethereal Plane. It has the benefit of not requiring any method of flight consuming your spell slots while you are building the pillar. Also, your castle will not have an area of "empty space" below it that you cannot pass through, so you can pull off cool tricks like making it appear to be held up by a dragon or something, without having a gap. Finally, it is permanant, while Walls of Force would need to be renewed every 2 minutes.

Alternatively, you could just embed a lot of Immovable Rods in it.

Arbitrarious

2011-06-06, 07:44 PM

I wish I owned that one...

And you can't make Reverse Gravity permanent, so that would be a temporary fix.

Permanency says other spells may be approved with DM approval. So it is a reasonable option. Alternately Wall of Force can be be made permenant explicitly. So you could make a foundation on a few immobile beams of force.

Lateral

2011-06-06, 07:49 PM

How much weight can, say, 20 immovable rods hold if placed strategically?

Tvtyrant

2011-06-06, 07:50 PM

160,000 pounds since they can each carry 8,000 lbs.

Which sounds like a lot but really isn't; we have semis that way that much. though for 100,000 GP it isn't terrible.

Lateral

2011-06-06, 07:51 PM

On their own, sure, but what about in a lattice? Or in triangle structures?

hivedragon

2011-06-06, 07:51 PM

In Escaflowne there is a type of mineral whose buoyancy defies it's density, levistone, or was it gravistone? Anywho, don't fret about material cost, just find some floating mountains and build your castle into the floating rock. You can also use smaller chunks of rock to build airships (similarly you can mine dragon hearts to power your magitech).

Edit: Then there were the floating mountains of JC's Avatar which no one thought it was worth the effort to explain so why should you?

Squiggles

2011-06-06, 07:54 PM

Shining South has the spell Suspension. It's a 4th level wizard/sorcerer and you can cause 1000lbs/level to levitate at your command for 1d4+ 1day/level. It would take a while but you could feasibly build multiple 'tiles' for your floating castle platform ala Permanency.

Marnath

2011-06-06, 07:57 PM

One other thing to suggest. Genesis (http://www.d20srd.org/srd/epic/spells/genesis.htm). It doesn't technically make a flying stronghold, but building a castle inside your own private demiplane would be way more secure/cool anyway.:smallsmile:

Madcrafter

2011-06-06, 08:02 PM

Hundreds of thousands of wizards, all concentrating on their own mage hand.

lianightdemon

2011-06-06, 08:07 PM

warforged wizards, so they don't ever get tired.

Flame of Anor

2011-06-06, 08:15 PM

On their own, sure, but what about in a lattice? Or in triangle structures?

The weakness isn't in the rods' connections to each other or the castle, it's in their magical anchorage to whatever, and you can't lattice that.

Ozreth

2011-06-06, 08:21 PM

Just have a castle that flys? Player's won't be fighting it will they?

I understand needing to have a reason behind it, but I don't understand having to justify it with game mechanics, pricing, etc.

Tvtyrant

2011-06-06, 08:26 PM

What if as a player I want to make one? :P And I could do it in epic easily, there are two different spells (nailed to the sky and provlic's flying city) that do exactly that.

Also, once you allow epic level characters into a setting it messes with everything. Why are there armies killing innocents if an epic level caster could simply casting Evilcide and destroy them all? Being able to do it pre-epic makes more sense for both the setting and the players.

What if it was an upside down pyramid, with a permanent Wall of Force for a platform at the bottom and another anchoring each side? You can make them 8 times as large at the top as the bottom, so the whole structure can be 1200 square ft. at the top at level 15, and around 300 ft tall. Adds up to a volume of 120,000 ft. cubed. So about the size of a highschool.

Lateral

2011-06-06, 08:26 PM

Just have a castle that flys? Player's won't be fighting it will they?

I understand needing to have a reason behind it, but I don't understand having to justify it with game mechanics, pricing, etc.

For fun. :smalltongue:

Tvtyrant

2011-06-06, 09:30 PM

Hmmm, I could always make some sort of permanent gate to another plane and push the reinforcing bars into it. I would just need a permanent source of a portal. Probably put the girders in Pandemonium as the least populated plane.

Mad Wizard

2011-06-06, 09:39 PM

Walls of force won't work - they have to be vertical.

Tvtyrant

2011-06-06, 09:44 PM

Walls of force won't work - they have to be vertical.

Or I just make it as a honey comb and make a few of them.

ericgrau

2011-06-07, 12:41 AM

Hmmm...

Custom item of greater tenser's floating disc, 8,000 gp per 100 lbs.
Carpet of flying 60,000 gp per 800 lbs., slightly cheaper.
Permanent reverse gravity item, 728,000 gp (7*13*2,000*4) for 6 10 foot cubes. A lot cheaper overall. You could build it up a lot higher above that foundation, especially if it's weighted for more upward force. Still not castle size though. Perhaps good for a floating tower since the foundation is limited but there isn't much of a weight limit as long as you pack the foundation full of lead rock (EDIT: cheaper).
Permanent wall of force item, 360,000 gp (9*5*2,000*4) each. Probably more painful overall since they're vertical and you need to make multiple.

A regular castle is already over a million which is more than level 20 wealth. How you supposed to make it fly too and still afford it? Do you mean pre-epic but still with the budget of a kingdom?

Alleran

2011-06-07, 01:06 AM

Pump your caster level to 35. Gate in an Elder Titan. Negotiate with it to have it use its Epic Spellcasting in a ritual to cast Proctiv's Move Mountain on a mountain you think is blocking your view and would be suitable as your new seaside (or mountain, or desert, or... yeah, whatever) retreat.

It'll create a floating mountaintop, flip it upside down, and give you a flying stronghold that you can build a city on.

Tvtyrant

2011-06-07, 02:02 AM

Well for the castle's price I figured I would either conquer one and bring it up in pieces, or just take a hug amount of rock up and make it using multiple castings of wall of stone, with iron wall to taste. For the keep I was going to use an Instant Fortress.

Honestly getting a big platform up into the sky is the real goal; anything you put on it is secondary.

Jacque

2011-06-07, 02:49 AM

Relics and Rituals I. It has a ritual called Raise the Keep. It requires a handful of arcane spellcasters (one of which must be able to cast level 8 spells), a dragon's heart, 50,000gp and a bit of xp. In return you get to enchant a castle with a permanent levitate spell which functions even in an antimagic field. It has a movement rate of 20 miles per day at perfect maneuverability.

NecroRick

2011-06-07, 06:25 AM

Put on your fancy pants and go talk nice to some Cloud Giants (p121 MM).

Legends tell of rare cloud giants that build castles on magical cloud islands isolated even from other cloud giants.

Also, Eberron's kingdom of Breeland had some *massive* floating fortresses that patrol it's borders.

Shadowknight12

2011-06-07, 06:40 AM

Permanent Image + Widen Spell + Heighten Spell + Caster Level Increases + Metamagic Reducers.

Disbelieve it and you fall right through.

CTrees

2011-06-07, 08:30 AM

Permanent Image + Widen Spell + Heighten Spell + Caster Level Increases + Metamagic Reducers.

Disbelieve it and you fall right through.

The emperor's new castle!

Actually this could be incredible. You can choose to fail your saves (as proven by "harmless" spells). Everyone you want to be in the castle, just tell them to keep voluntarily failing. Anyone who attacks, doesn't have that warning, gets their save as normal, possibly falls down hundreds of feet. Also, can't you voluntarily lower the DC of saves on a spell? "Oh, the save is DC 1. You have to be exceedingly lucky/unlucky to fail."

Am I looking into this properly? Because... it sounds almost too fun not to try, now.

Shadowknight12

2011-06-07, 09:13 AM

The emperor's new castle!

Actually this could be incredible. You can choose to fail your saves (as proven by "harmless" spells). Everyone you want to be in the castle, just tell them to keep voluntarily failing. Anyone who attacks, doesn't have that warning, gets their save as normal, possibly falls down hundreds of feet. Also, can't you voluntarily lower the DC of saves on a spell? "Oh, the save is DC 1. You have to be exceedingly lucky/unlucky to fail."

Am I looking into this properly? Because... it sounds almost too fun not to try, now.

Yeah, you can willingly fail your saves, but you have to be aware of the spell in order to do so. You have to know that you'll be under the effect of the illusion in order to willingly fail your save against it. If you don't know that the castle is illusory, you'd get an automatic save when you interact with it. The problem is that the attacker can ALSO willingly fail his save, because he ostensibly knows that the castle is also an illusion.

No, no, you don't want the DC to be low. You want it to be high. You want Heighten Spell, a boost in your casting ability modifier, the Irresistible Spell, anything you have to make the DC as high as possible. If you want an attacker to "fall right through" just tell them that the castle is an illusion and buff their saves. Or keep a "bouncer" of sorts nearby to get rid of unwanted guests. Just make them a naturally flying creature with an antimagic field.

EDIT: The only problem I see with this castle is that 5% of people who don't know it's an illusion will fall right through nonetheless.

Drogorn

2011-06-07, 09:28 AM

EDIT: The only problem I see with this castle is that 5% of people who don't know it's an illusion will fall right through nonetheless.

How about putting a very real stone floor on top of the illusory floor?

Shadowknight12

2011-06-07, 09:35 AM

How about putting a very real stone floor on top of the illusory floor?

Bugger, I found a flaw in my plan:

Because figments and glamers (see below) are unreal, they cannot produce real effects the way that other types of illusions can. They cannot cause damage to objects or creatures, support weight, provide nutrition, or provide protection from the elements.

We need something with the [Shadow] descriptor:

A shadow spell creates something that is partially real from extradimensional energy. Such illusions can have real effects. Damage dealt by a shadow illusion is real.

The other problem is that objects automatically succeed their Will saves versus the Shades, Shadow Evocation and Shadow Conjuration lines of spells. Surely there must be a [Shadow] spell somewhere that doesn't have this flaw.

You all know what this means. It's obscure splatbook hunting time!

Lateral

2011-06-07, 01:22 PM

Shadowcraft Magery? I don't remember if it has this clause.

Tvtyrant

2011-06-07, 03:13 PM

I like where the real/illusionary castle in the sky is going.

DarthCyberWolf

2011-06-07, 03:38 PM

The other problem is that objects automatically succeed their Will saves versus the Shades, Shadow Evocation and Shadow Conjuration lines of spells. Surely there must be a [Shadow] spell somewhere that doesn't have this flaw.

You all know what this means. It's obscure splatbook hunting time!

Shadowcraft Mage with Heighten Spell and the +20% realness feat (forget the name). I would think the will save wouldn't matter anymore if it's 100% real (or more(?)) anyway.

Shadowknight12

2011-06-07, 11:44 PM

Shadowcraft Mage with Heighten Spell and the +20% realness feat (forget the name). I would think the will save wouldn't matter anymore if it's 100% real (or more(?)) anyway.

Okay, but even so, those spells duplicate other spells. As I read the descriptions, they don't allow for freedom of creation. Furthermore, apparently those spells don't have a fixed Duration, instead lasting as long as the spell they're mimicking, so a Shades-created Wall of Force would last just as much as a regular Wall of Force.

Nightmare Terrain from Complete Mage could be used to make a castle, but you'd need some heavy DM fiat to do this ("it's up to the caster whether the spell entangles or not," "it can look like a regular castle since I'm sure that's someone's nightmare," "the concealment effect is optional or can be remedied by bringing lots of light sources into the castle," etc) and it has to be made permanent with Permanency or else it's just a big waste of time. All in all, a terrible spell.

Shadow Landscape from Complete Divine is pretty much Nightmare Terrain on steroids. Lots of the same problems apply as well.

Spell Compendium proved to be hilariously disappointing.

Frostburn, however, gave me an idea: Ice Castle. How to get it up into the air is the tricky part, but once you solve that, you can make it permanent with the Permanency spell (would cost 3500 XP as per the Phase Door example, a spell of the same level) and then you can use the Permanent Image trick I mentioned originally to disguise the ice and snow to ordinary wood, stone and anything else you can think of (remember it provides thermal elements as well, so you can make an ice wall look and feel like it's made of hot iron).

The problem is how to get it up in the air. Column of Ice is of dubious utility. Depends a lot on the DM's interpretation of the spell. On the bright side, it's already permanent. With a similarly liberal interpretation, Ice Shape can be used to shape the ice/snow under the castle in order to raise it to the skies (while remaining tethered to the ground by a hair-thin string of ice). Failing that, you can use Telekinesis to lift 375 pounds of snow into the air (forming a flat surface), then cast a permanent Ice Castle on top of that. If your DM rules that the castle only stays aloft for as long as the Telekinesis effect is maintained, just spring another 1500 XP for another Permanency spell.

Disadvantages of the ice castle:

Must be in freezing temperatures or it will melt (actually not a problem at a high enough altitude, check with your DM). Possible fix: the Blizzard spell made permanent (also 'concealable' with illusions).
Vulnerability to fire damage. Possible fix: Diverse forms of energy resistance/immunity.
Dispelling and antimagic. Possible fix: Pending further investigation.

EDIT: Or just use a Wish, dammit. :smallamused:

Tvtyrant

2011-06-08, 12:16 AM

crazyhedgewizrd

2011-06-08, 01:52 AM

permanent levitate of the base of the building, 10,000gp per tonne CL 20.
Only good for a light building.

Shadowknight12

2011-06-08, 01:53 AM

Well Ice Castle could be used to make a really cool floating (on water) castle, and then Hallow+endure elements to keep it cold.

Would making an Instant Fortress into an item familiar and then investing Overland Flight into it work? If you invest it several times you eventually get a castle that never has to land.

Funny how Hallow says "building" but then the actual spell description says "40-ft. radius emanating from the touched point." Which can be widened to 80-ft. radius with Widen Spell, but that's about it.

The latter is actually a good idea, and I don't see why it wouldn't work. The problem is that it requires periodic renovation of spells. The wizard in charge couldn't take a sick day without the fortress plummeting from the skies. But I suppose that since you can invest XP into the item familiar, you could make it cast Permanency as well, so that the Overland Flight would be permanent.

The antimagic/dispel issue is still a problem, since a DM would no longer need to say "Rocks fall, everyone dies." Merely "Dispel Magic happens, everyone falls. Then everyone dies."

The idea of a flying Instant Fortress as an item familiar is hilarious. Sneak it into the king's bedchamber through the window, then activate the command word to enlarge it. Most epic assassination ever.

crazyhedgewizrd

2011-06-08, 01:59 AM

The antimagic/dispel issue is still a problem, since a DM would no longer need to say "Rocks fall, everyone dies." Merely "Dispel Magic happens, everyone falls. Then everyone dies."

Pernament spells that were dispelled, will reactivate in 1d4 rounds. depend on how high the building is, you will probably wont die.

Tvtyrant

2011-06-08, 02:03 AM

Actually I think the idea of a flying castle item familiar would be fantastic for an eccentric caster; he can keep it with him by shrinking it and live in it each day.

Shadowknight12

2011-06-08, 02:04 AM

Pernament spells that were dispelled, will reactivate in 1d4 rounds. depend on how high the building is, you will probably wont die.

Hahahaha, no. Sadly, no. I only wish it was like that.

Spells cast on other creatures, objects, or locations (not on you) are vulnerable to dispel magic as normal.

EDIT: Whoops, wrong quote.

This application of permanency can be dispelled only by a caster of higher level than you were when you cast the spell.

From Permanency (http://www.d20srd.org/srd/spells/permanency.htm).

Granted, an antimagic field might not make the entire fortress fall, but depending on where it's located, it could generate a lot of structural damage as part of the fortress is "pulled down" by gravity while other parts of it are not.

Tvtyrant

2011-06-08, 02:10 AM

But if your using the Share Spell ability the permanent Overland Flight is on both you and your familiar, so it wouldn't be dispelled.

Thiyr

2011-06-08, 02:14 AM

What if it was an upside down pyramid, with a permanent Wall of Force for a platform at the bottom and another anchoring each side? You can make them 8 times as large at the top as the bottom, so the whole structure can be 1200 square ft. at the top at level 15, and around 300 ft tall. Adds up to a volume of 120,000 ft. cubed. So about the size of a highschool.

One might almost say that this would be an Inverted Pyramid.

As I assume this is far from common knowledge, I will explain. The Inverted Pyramid is the mage's guild in Ptolus, Monte Cook's campaign setting. They conveniently reside in an invisible flying upside-down pyramid, held aloft by rocks which have negative weight, Heliothil. For every 1 pound it should weigh, it instead weighs -5, priced at 100gp per negative pound. Nonmagical, too! So if you can use some form of magic to locate large quantities of this, or can purchase enough, that would serve you. Just kinda expensive for your purposes, I'd think. And I'd personally not want to bother mathing out just how much would be needed to get to the proper altitude/size of building.

crazyhedgewizrd

2011-06-08, 02:17 AM

Hahahaha, no. Sadly, no. I only wish it was like that.

the text in dispel magic

If the object that you target is a magic item, you make a dispel check against the item’s caster level. If you succeed, all the item’s magical properties are suppressed for 1d4 rounds, after which the item recovers on its own. A suppressed item becomes nonmagical for the duration of the effect. An interdimensional interface (such as a bag of holding) is temporarily closed. A magic item’s physical properties are unchanged: A suppressed magic sword is still a sword (a masterwork sword, in fact). Artifacts and deities are unaffected by mortal magic such as this.

so the buildings magic will kick back in.

if you are referring to a disjunction then it is a permanent removel of spell. i will agree that a antimagic field will cause a lot of damage to the structure, but outside of the antimagic field the spells should reactivate.

Shadowknight12

2011-06-08, 02:20 AM

But if your using the Share Spell ability the permanent Overland Flight is on both you and your familiar, so it wouldn't be dispelled.

You can't share spells with an item familiar. With a normal familiar, sure, but you can't have an item familiar as a regular familiar. Those are completely different mechanics.

Furthermore, Dispel Magic says that a dispelled effect ends when successfully dispelled. That means that, as per the Share Spells rule:

If the spell or effect has a duration other than instantaneous, it stops affecting the familiar if it moves farther than 5 feet away and will not affect the familiar again even if it returns to the master before the duration expires. Additionally, the master may cast a spell with a target of "You" on his familiar (as a touch range spell) instead of on himself.

A familiar can be the target of a dispel, and if its Overland Flight effect is dispelled, it does not regain it (and the wizard's own Overland Flight remains active as normal). Likewise, if the wizard's Overland Flight effect is dispelled, he does not regain it (and the familiar's own Overland Flight remains active as normal).

For all intents and purposes, it's as though the familiar had received a free casting of whatever spell the wizard cast on himself, which gets dispelled if the familiar moves more than 5 feet away.

But again, an item familiar is not a wizard or sorcerer's familiar. :smalltongue:

EDIT:

the text in dispel magic

so the buildings magic will kick back in.

if you are referring to a disjunction then it is a permanent removel of spell. i will agree that a antimagic field will cause a lot of damage to the structure, but outside of the antimagic field the spells should reactivate.

Overland Flight, even if it's made permanent, is not a property of the magic item. It is an extraneous spell affecting the item. The item familiar has properties, yes, and those, if targeted by Dispel Magic, will only be temporarily suppressed. Any buffs that might be cast onto it are, unfortunately, not considered "properties." Not even if they've been made permanent.

Tvtyrant

2011-06-08, 02:25 AM

crazyhedgewizrd

2011-06-08, 02:37 AM

Overland Flight, even if it's made permanent, is not a property of the magic item. It is an extraneous spell affecting the item. The item familiar has properties, yes, and those, if targeted by Dispel Magic, will only be temporarily suppressed. Any buffs that might be cast onto it are, unfortunately, not considered "properties." Not even if they've been made permanent.

who in their right mind, would have a flight or lavitation ability as a buff on a building.

Tvtyrant

2011-06-08, 02:38 AM

who in their right mind, would have a flight or lavitation ability as a buff on a building.

But some people aren't in their right mind :D (me)

I suppose you could add levitation to the familiar as an item effect.

A castle with boots of levitation on would be hilarious.

crazyhedgewizrd

2011-06-08, 02:44 AM

silly idea, build on the ethereal plane, and have a force effect on yourself so you can walk around your house on the material plane.

Shadowknight12

2011-06-08, 02:50 AM

More importantly they would have to fly up to my castle to get near me, and I can always cast Magnificent Mansion and come out after the castle has hit the ground. I think the item familiar has the most promise honestly, though I do like the illusionary castle idea.

Could you heal the item as a creature? If so the instant fortress item gets really powerful.

I've been looking to more sourcebooks, but not being an expert in illusions, I can't really say I've found anything worth mentioning. [Shadow] spells are actually very limited in what they do.

who in their right mind, would have a flight or lavitation ability as a buff on a building.

Well, if it gets you a flying building...

But some people aren't in their right mind :D (me)

I suppose you could add levitation to the familiar as an item effect.

A castle with boots of levitation on would be hilarious.

Wouldn't work. A pair of levitation boots don't levitate if left on their own (otherwise you'd have to keep them tied to your bed at night). They make the wearer levitate. And since a fortress does not fit into any sort of body slot, you can't gain the effect.

A castle, similarly, does not have any item slots either, so you can't put levitation boots on them.

silly idea, build on the ethereal plane, and have a force effect on yourself so you can walk around your house on the material plane.

Um. No. It does not work like that. There are actually numerous problems with that idea. Firstly, how do you build in the ethereal plane? With what materials? Secondly, what do you mean by a "force effect"? Thirdly, you need to see into the ethereal plane in order to affect it, so you'd need True Seeing on top. Fourthly, even if we skip all this and just assume it works, you're not getting a castle on the material plane. Unless you use the Permanent Image trick to pretend you do. But it won't protect you from the elements and you wouldn't be able to drop an object or it would pass right through.

Tvtyrant

2011-06-08, 02:56 AM

Shadowknight12

2011-06-08, 03:40 AM

Well I have one that would work for a permanent sky castle unless someone hit the buttons: Cubic Gate and then pillars into random places on other planes. Then build something over the cube so no one can get near it and your basically good.

Um. No? Well, kinda? Okay, you can use a Cubic Gate to open a gate to another plane, build a pillar there and use it to support the cube. But you can't build an entire castle and support it on a cube! And if you could, that still means that the gate must be left permanently open, which means a 10% chance per minute of a random outsider sneaking into your castle! And may I remind you of the tons of outsiders printed out there? Which have all sorts of terribly nasty abilities and are really hard to prepare against?

It makes for an excellent adventure location, however.

Dr.Epic

2011-06-08, 03:46 AM

You could just homebrew something.

Tvtyrant

2011-06-08, 04:50 AM

You could just homebrew something.

But then I would need DM permission! As opposed to needing DM permission. :P

myancey

2011-06-08, 10:21 PM

Provided you've the standard wealth by character level, you could design an awesome castle by 20, with 760,000gp.

You gotta have the Stronghold Builder's Guidebook.

You need:

Landlord, the feat:

http://www.realmshelps.net/cgi-bin/featsform.pl

Stone Shape, the spell. It's instantaneous duration...so permanent.

Create Undead and Control Undead, because in Stronghold Builders', using undead as your workforce for construction eliminates the wages section of building a stronghold...which usually runs 50%. The Stone Shape is for crafting your walls and floors..eliminating the cost of supplies...aside from brains (bad zombie joke).

It actually lists costs for putting a permanent wall of force around your stronghold for defense, or even for crafting it as the stronghold. It gives costs for making your stronghold teleporting, planeshifting, floating, and moving. The magical extras are all you'd really have to pay for.

Arbitrarious

2011-06-08, 10:46 PM

But then I would need DM permission! As opposed to needing DM permission. :P

Really the wall of force solves it. It's 1in thick. You cast 4 of them into a large square at the desired location. Lay a floor with reinforced beams. Magically hardened materials (a couple spells can harden items permanently) work well and you can create drop downs that hang off the top of wall down the sides to join braces from the middle of the floor so it doesn't sag. Seal the bottom of the square in a similar fashion and you are done.

So long as the material of that first cube is strong enough you've basically pulled a minecraft (building an entire castle from 1 floating brick). And it's all RAW friendly with no shenanigans needed, except for Knowledge (architecture and engineering).

Edit: A thought, can you glue something to a wall of force? If so sovereigns glue could be used to fasten supports to the side of the wall as well.