# Addition looks like it is on a deck...lack of a better term



## Bondo (Dec 8, 2007)

Ayuh,...

That's just an addition built on a Post,+ Pier foundation...


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## Termite (Apr 13, 2008)

The piers that would support a deck will typically be inadequate for support of a habitable living space. It is certainly possible to build an addition this way, but _much larger piers and bearing structure_ would be required. An engineer is needed to determine the correct pier size. So, you normally can't throw a roof and walls on what was an exterior deck and expect it to perform structurally.

Personally, I see few advantages to this configuration. Insulating the floor adequately is very important, and any plumbing in the room is a real challenge. Personally, I'd opt for a slab on grade with trench footings instead...Much warmer and less cheesy of a design. If grade is too low, go with a poured footing/foundation and framed floor over a crawlspace.


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## AtlanticWBConst. (May 12, 2006)

That's an addition built on pier footings (as already stated).

Some of the Pros: 
Save on costs of excavation work, soil removal, form-work, and amount of concrete. Less cost overall to do, than a full foundation addition.


Some of the cons: 
Enclosed room's flooring, may not be as stable as a full enclosed foundation (May affect tile work).
Space underneath is somewhat open to the elements. In the case of any plumbing there; even closed and insulated, pipes can freeze.
Some don't like the look of a room attached to the house without a foundation like the rest of the house has.
Joist area underneath should be closed-off if Pressure Treated lumber or other non-resistant lumber is not used.

The majority of room additions built on pier footings are designed to be used as 3-season rooms. Such purpose means that they may not have any electrical, they have no insulation, 
no Low-e rated windows, and no source of heat.

If two floor levels are to be added, as opposed to a single floor room addition, standard pier footings will not necessarily support the added load.


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## Melissa1 (Jan 9, 2009)

Thanks for the responses.

I would NOT be doing an addition on an existing deck, it would be a new structure. It would extend out only 7.5 feet. There would be a bathtub (no sink or toilet) but the plumbing would run an interior wall, not the floor.

I can do a regular foundation running from the basement, but I have many major systems it would disrubt, such as my above ground main sewer line (very old house), an outside grinder pump, and my basement water drainage system. I suspect that altering these major systems will cost a ton of money for 7.5 feet. Not to mention, I do not need, nor want the extra 7.5 feet in the basement.

Of course, I don't want something that is not structurally sound or good for the long term. I also would definitly need this for a 4 season room as it is adding closet space and a larger bath onto my MBR.

i would love to hear anyone else's input/thoughts.


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## Termite (Apr 13, 2008)

If you're installing a bathtub, your tub's drain plumbing will in fact have to be in the floor. There's no way around that.


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## Melissa1 (Jan 9, 2009)

thekctermite said:


> If you're installing a bathtub, your tub's drain plumbing will in fact have to be in the floor. There's no way around that.


Of course, but the potential freezing issue (I'm in the south, so it can happen, but not as likely as in other areas) is minimized since it is drain pipe and not a supply line? No?


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## Termite (Apr 13, 2008)

Your trap always has water in it. The remainder of the pipe will drain dry. The trap will freeze quite easily and block the drain, probably break it as well. There are electrical tape products that can be used to heat pipes.


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## Melissa1 (Jan 9, 2009)

thekctermite said:


> Your trap always has water in it. The remainder of the pipe will drain dry. The trap will freeze quite easily and block the drain, probably break it as well. There are electrical tape products that can be used to heat pipes.


Got it, so basically because of the smaller volume of water, it is actually probably more likely to freeze if it got so cold.

Thanks!


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## Bondo (Dec 8, 2007)

Melissa1 said:


> Got it, so basically because of the smaller volume of water, it is actually probably more likely to freeze if it got so cold.
> 
> Thanks!


 
Ayuh,...

Actually,... It's the fact that it's Standing Water,... ei; Not Moving...
It has ittle to do with the Volume involved...


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## dweathington (Jan 29, 2010)

*Addition on to house from a deck*

Hi,
My name is Dorothy and I am new to this forum and your pics are the same ideal i have for remodeling on my Deck. I would like to turn my deck into a room but I got this rediculous price for doing this 20,000.00 dollars. I don't think this is a good price. Have you had an estimate done for something like this. If so, I would like to know how much. My room would be a 16 x 16 if this information help. I don't know a lot about pricing for a room but I think this is a bit much. Anyone, that can help me please. I would like 4 windows and a standard door.

Thank you,
Dorothy


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## Scuba_Dave (Jan 16, 2009)

dweathington said:


> Hi,
> My name is Dorothy and I am new to this forum and your pics are the same ideal i have for remodeling on my Deck. I would like to turn my deck into a room but I got this rediculous price for doing this 20,000.00 dollars. I don't think this is a good price. Have you had an estimate done for something like this. If so, I would like to know how much. My room would be a 16 x 16 if this information help. I don't know a lot about pricing for a room but I think this is a bit much. Anyone, that can help me please. I would like 4 windows and a standard door.
> 
> Thank you,
> Dorothy


Pricing varies by area & specific job
This is a DIY site, not a pricing site
Get several local estimates & checxk references


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## AtlanticWBConst. (May 12, 2006)

dweathington said:


> Hi,
> My name is Dorothy and I am new to this forum and your pics are the same ideal i have for remodeling on my Deck. I would like to turn my deck into a room but I got this rediculous price for doing this 20,000.00 dollars. I don't think this is a good price. Have you had an estimate done for something like this. If so, I would like to know how much. My room would be a 16 x 16 if this information help. I don't know a lot about pricing for a room but I think this is a bit much. Anyone, that can help me please. I would like 4 windows and a standard door.
> 
> Thank you,
> Dorothy


$20K sounds very reasonable to me. I am not sure what you are basing your price comparision, and evaluation to?

Have you had something like this done before, in the last several years?

Realize that just because there is a deck there, does not mean the cost will be cut in half.

FWIW - We have done quite a few of these. 

There is a lot of work involved, much more than simply slapping-up 4 walls and a roof. Realize that the $20K is made up of a lot of smaller project cost numbers. Example: 

- The existing home's roof needs to be tied into the new roof = more work & money = home's roof materials removed/demolition, and added materials for the home's roof itself.
- The new room's siding and wall, must be tied into the existing home's exterior walls & siding = demolition, and added materials for the home itself.
- Low-e doors and windows are not cheap. 
- Insulation
- If you want to have *heat & electrical*, that can add $3K-$4K, if your current home system requires upgrading to do that, it can add more.
- Drywall
- Painting
- Exterior finishes (siding & trim)
- Permits & fees
- City/town inspections = time = $
- Modification of the entryway into the new room from the home (if planned)
- Required drawings for permit
- Interior trimwork
- Trash haul out
- Flooring materials
- Roofing materials
- Gutters?
- Exterior entry stairs and concrete stair pad (if planned)
- Attached deck? = $$
- Etc, etc, etc....

A room has a lot more weight that needs to be supported, than a deck. Sometimes, it is even better to rip the deck down, and start over by creating the pier footings and structure that is better suited, and stronger to support the new room (walls, floor, roof, additional roof weight (snow loads), sheetrock, windows, etc)

When I apply for a permit for such a project, I have to provide a complete set of structural framing plans to the building Dept (floor, roof, ceiling, 3 walls, and any beam calculations). I charge for the time involved to produce/create such detailed plans. It is part of the scope of the project.

FWIW - I now do a breakdown of the entire projects using smaller numbers, that equal out to the final large numbers. I do this, so that my potential Clients can see where the final price has derived from.
I also lay out the entire sequence of what is to take place, so that Home Owner's can see the large amount of work and multiple phases that are involved to start & complete such a project.


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## Willie T (Jan 29, 2009)

$20k seems very reasonable. It would run an additional 25% or more here.


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