Thread: why is soil/sand poured in a tub hole drainage pipe before installation?

Just wondering

why is soil/sand poured in a tub hole drainage pipe before installation?

Never heard of that being done.

That would be a risky way to try to keep concrete, grout, and other stuff out of the pipe - capping the pipe with a test cap is what I always see done ... and capping pipe needs to be done anyway so the underground piping can be tested with minimum 5 feet of head (which recently went to 10 feet of head).

Originally Posted by Jerry Peck

why is soil/sand poured in a tub hole drainage pipe before installation?

Never heard of that being done.

That would be a risky way to try to keep concrete, grout, and other stuff out of the pipe - capping the pipe with a test cap is what I always see done ... and capping pipe needs to be done anyway so the underground piping can be tested with minimum 5 feet of head (which recently went to 10 feet of head).

The bathroom is in the basement and it is unfinished, you can see the sink drainage pipe cover with tape but for the toilet its just a wood frame with sand(no fixtures have been installed)

Originally Posted by Fernando rojas

The bathroom is in the basement and it is unfinished, you can see the sink drainage pipe cover with tape ...

Should have a test cap glued on (if plastic pipe) or a cap (suitable for the metal used), plastic (ABS and PVC could also have a clean out fitting with clean out plug, while that's a bit overkill there would not be anything wrong with that).

... but for the toilet its just a wood frame with sand(no fixtures have been installed)

Okay, the pipe is not filled with sand, but the hole in the slab is filled with sand around the pipe? Or is the pipe itself also filled with sand? The pipe should be capped the same as above for the sink pipe.

Potential additional questions about the wood frame filled with sand if termite treatments are used in your area.

Originally Posted by Jerry Peck

Should have a test cap glued on (if plastic pipe) or a cap (suitable for the metal used), plastic (ABS and PVC could also have a clean out fitting with clean out plug, while that's a bit overkill there would not be anything wrong with that).



Okay, the pipe is not filled with sand, but the hole in the slab is filled with sand around the pipe? Or is the pipe itself also filled with sand? The pipe should be capped the same as above for the sink pipe.

Potential additional questions about the wood frame filled with sand if termite treatments are used in your area.

the hole in the slab is filled with sand around the pipe not the pipe.

In this case I believe it would be safe to say a picture would be worth a thousand words.

Originally Posted by Fernando rojas

Just wondering

So concrete will not get poured in to it. There are better ways of doing it.

Originally Posted by Fernando rojas

the hole in the slab is filled with sand around the pipe not the pipe.

They likely did that for lack of planning and not knowing what to do (based on the way I've always seen it done).

I've always seen the concrete poured up to and surrounding the pipe, with the pipe sticking up above the concrete with a test cap glued on. (Note: the discussion changed from "tub" to "toilet").

Leaving an opening around the tub trap pipe was common practice for decades, now plastic recessed tubs are cast in with the concrete and the space in the recessed plastic tub gives the working room needed.

A nod is as good as a wink to a blind horse. - Rod Stewart

A photo would really help.

I'd bet that when you dig down a bit, you'd find a properly capped pipe under the sand.
Around here, they fill the opening with gravel to remove the trip hazard, but the pipe is under there waiting to be used.

Erby's photo shows a shower drain opening (a tub drain opening will be at one end) and the toilet pipe sticking up as I described it would be.

Erby, is termite pretreatment required in your area? if so, that should have a plastic pan cast into the concrete with the pipe in it (instead of just being open to dirt below), and, yes, they could fill that with gravel to reduce the trip hazard.

I've never seen a plastic pan cast in the concrete in my area.

Hey does a plastic pan stop termites?

Originally Posted by Jerry Peck

Erby's photo shows a shower drain opening (a tub drain opening will be at one end) and the toilet pipe sticking up as I described it would be.

Erby, is termite pretreatment required in your area? if so, that should have a plastic pan cast into the concrete with the pipe in it (instead of just being open to dirt below), and, yes, they could fill that with gravel to reduce the trip hazard.

Thanks everyone for your thoughts It really helped a lot.

Originally Posted by Jack Feldmann

I've never seen a plastic pan cast in the concrete in my area.

Originally Posted by John Kogel

Hey does a plastic pan stop termites?

From the IRC:
- R318.1 Subterranean termite control methods. - - In areas subject to damage from termites as indicated by Table R301.2(1), methods of protection shall be one of the following methods or a combination of these methods:
- - - 1. Chemical termiticide treatment, as provided in Section R318.2.
- - - 2. Termite baiting system installed and maintained according to the label.
- - - 3. Pressure-preservative-treated wood in accordance with the provisions of Section R317.1.
- - - 4. Naturally durable termite-resistant wood.
- - - 5. Physical barriers as provided in Section R318.3 and used in locations as specified in Section R317.1.
- - - 6. Cold-formed steel framing in accordance with Sections R505.2.1 and R603.2.1.


- - R318.2 Chemical termiticide treatment.
- - - Chemical termiticide treatment shall include soil treatment and/or field applied wood treatment. The concentration, rate of application and method of treatment of the chemical termiticide shall be in strict accordance with the termiticide label.

Leaving the opening for the tub and shower drains, or any opening in the slab for that matter, makes it extremely difficult to apply the chemical (soil) treatment in accordance with the label. The termite applicator would need to go back multiple times, and that (in the great majority of cases) 'just ain't gonna happen' (and it seldom does happen), even when the contractor know what needs to be done, if the applicator can't/doesn't make it back to re-treat when he is supposed to ... work does not stop, it just gets covered up.

To solve that problem, the Florida code added these requirements (Florida is a high termite pressure area): (bold and underlining are mine)
- R318.1 Termite Protection.
- - Termite protection shall be provided by registered termiticides, including soil applied pesticides, baiting systems, and pesticides applied to wood, or other approved methods of termite protection labeled for use as a preventative treatment to new construction. See Section 202, REGISTERED TERMITICIDE. Upon completion of the application of the termite protective treatment, a Certificate of Compliance shall be issued to the building department by the licensed pest control company that contains the following statement: "The building has received a complete treatment for the prevention of subterranean termites. Treatment is in accordance with rules and laws established by the Florida Department of Agriculture and Consumer Services.”
- - R318.1.1
- - - If soil treatment used for subterranean termite prevention, the initial chemical soil treatment inside the foundation perimeter shall be done after all excavation, backfilling and compaction is complete.
- - R318.1.2
- - - If soil treatment is used for subterranean termite prevention, soil area disturbed after initial chemical soil treatment shall be retreated with a chemical soil treatment, including spaces boxed or formed.
- - R318.1.3
- - - If soil treatment is used for subterranean termite prevention, space in concrete floors boxed out or formed for the subsequent installation of plumbing traps, drains or any other purpose shall be created by using plastic or metal permanently placed forms of sufficient depth to eliminate any planned soil disturbance after initial chemical soil treatment.
- - R318.1.4
- - - If soil treatment is used for subterranean termite prevention, chemically treated soil shall be protected with a minimum 6 mil vapor retarder to protect against rainfall dilution. If rainfall occurs before vapor retarder placement, retreatment is required. Any work, including placement of reinforcing steel, done after chemical treatment until the concrete floor is poured, shall be done in such manner as to avoid penetrating or disturbing treated soil.
- - R318.1.5
- - - If soil treatment is used for subterranean termite prevention, concrete overpour or mortar accumulated along the exterior foundation perimeter shall be removed prior to exterior chemical soil treatment, to enhance vertical penetration of the chemicals.
- - R318.1.6
- - - If soil treatment is used for subterranean termite prevention, chemical soil treatments shall also be applied under all exterior concrete or grade within 1 foot (305 mm) of the primary structure sidewalls. Also, a vertical chemical barrier shall be applied promptly after construction is completed, including initial landscaping and irrigation/sprinkler installation. Any soil disturbed after the chemical vertical barrier is applied shall be promptly retreated.
- - R318.1.7
- - - If a registered termiticide formulated and registered as a bait system is used for subterranean termite prevention, Section R318.1.1 through Section R318.1.6 do not apply; however, a signed contract assuring the installation, maintenance and monitoring of the baiting system for a minimum of five years from the issue of the Certificate of Occupancy shall be provided to the building official prior to the pouring of the slab, and the system must be installed prior to final building approval.
- - - If the baiting system directions for use require a monitoring phase prior to installation of the pesticide active ingredient, the installation of the monitoring phase components shall be deemed to constitute installation of the system.
- - R318.1.8
- - - If a registered termiticide formulated and registered as a wood treatment is used for subterranean termite prevention, Sections R318.1.1 through R318.1.6 do not apply. Application of the wood treatment termiticide shall be as required by label directions for use, and must be completed prior to final building approval.


The underlined and bold text is there because it is widely acknowledged that applications do not come back (for various reasons) and treat all the areas which are required to be treated by the label, or are simply not called back to treat those areas.

However, *not being in the code* does not mean something does not need to be done to address this known issue. The language in the Florida code solves that problem (except for when the plastic boxes are set to high and have to be removed to dig deeper, but at least it gives the inspector a heads up on seeing it and catching it.

Those plastic boxes are readily available as they are used all over Florida, and are an excellent way to address the same issue/problem where the code does not specifically call for them (where the label calls for additional treatment trips which are not made).

And, yes, those plastic boxes do stop termites. Metal is seldom used as the metal would need to be corrosion resistant, would rust out relatively early anyway, and would cost a lot more than the plastic boxes.

Florida code may not apply in other States.
The OP is not in Florida.

Originally Posted by Jack Feldmann

Florida code may not apply in other States.
The OP is not in Florida.

The Florida code *doesn't* apply to other states.

The reason I posted the Florida code (and which I thought I was clear on) was the posting of the IRC code ... that doing what is required by the labeling *is* required by the IRC ... and because it is rare that the labeling is followed *all the way through* (for the reasons I explained) ... the Florida code is *one way* to address it to know the labeling is being followed (to the extent one can "know" that) ... and that the Florida code method could be applied in other areas to address the labeling issues which are not being followed.

Yes, termite pre-treatment is required in most jurisdictions around here, but that's what you get. Every now and then the form will still be there.

Out of curiosity, do any of you know much about the action of these termiticides? Are they intended to form a "solid" barrier of poison around the foundation, under walkways, etc? How specific are they to termites? Do they leach into the surrounding soil? It must be some pretty heavy-duty stuff to retain its effectiveness, and I have to wonder how it affects other soil critters, and animals that eat termites.

Originally Posted by Kristi Silber

Out of curiosity, do any of you know much about the action of these termiticides?

The ones I am familiar with interfere with the life cycle of the termite, so they would really only be effective on termites (or possibly on something very similar).

Are they intended to form a "solid" barrier of poison around the foundation, under walkways, etc?

Define "solid ... ... they form a continuous chemical barrier within the soil, but I would not define it as being "solid".

How specific are they to termites?

See above.

Do they leach into the surrounding soil?

Not much, they would lose their effectiveness if they dissipated like that.

It must be some pretty heavy-duty stuff to retain its effectiveness,

It used to be heavy-duty stuff ... now it is not very effective.

and I have to wonder how it affects other soil critters, and animals that eat termites.

That's why it is not heavy-duty stuff anymore.

Used to be chlordane:
- Chlordane | Technology Transfer Network Air Toxics Web site | US EPA
- see first line under "Uses"

Chlordane would last 50 years or more under a slab or in the soil, the stuff used nowadays may last 5 years ... IF it is applied per the label - and that is rare, usually it is watered down as it is kind of expensive, and watering it down makes it almost useless.

Hmm, the fact that it interferes with the life cycle of termites really says nothing about how specific it is. Depends on what it attacks. However, termites are in a family of their own, Isoptera, so it's quite possible the action is specific to them.

That's why "solid" was in parentheses! "Solid" meaning here an envelope impenetrable by termites.

If it only last 5 years, what's the bloody point!? How ridiculous.

Originally Posted by Kristi Silber

Hmm, the fact that it interferes with the life cycle of termites really says nothing about how specific it is. Depends on what it attacks. However, termites are in a family of their own, Isoptera, so it's quite possible the action is specific to them.

That's why "solid" was in parentheses! "Solid" meaning here an envelope impenetrable by termites.

If it only last 5 years, what's the bloody point!? How ridiculous.

As I recall, the termiticides keep the termites from progressing out of the nymph stage.

My recollection is 5 years - thus their 5 year warranty. It may last longer, but not anywhere like chlordane lasted.