Basements...Poured Concrete or Cinder Blocks?

Poured concrete is a solid piece, whereas block is many pieces. The more pieces, the more places things can fail. If the house has a proper moisture barrier on the outside of the foundation, it shouldnt matter for moisture penetration, but again... one piece vs. many. I dont think I'd pass on a house soley because its block, unless a home inspector found something wrong with it.

Your studs go from the toe plate on the floor, to the header attached to your joists above, so it shouldnt matter what its made out of for framing walls. I wouldnt frame a wall directly to the foundation walls. When you frame the walls, you'll fill the stud bays with insulation, and you can put in whatever R value you want. A few feet underground, the temp is more or less constant anyways, so the basement shouldnt need much help from the HVAC. Make sure you do put in an air return in the basement when you finish it off. You'll want that air recirculated through the unit for humidity control.

May just be a matter of symantics... But be sure to distinguish between cinder blocks and concrete blocks.  The latter are preferred nowaday since they are produced with more dense aggregate.  I would definitely not build or buy a home with "cinder block" construction.

As to the difference between concrete block or poured concrete... If building a custom home, I'd go with concrete block foundation.  However, if I were buying a home already constructed, neither concrete block nor poured concrete would rule the house out if it had an otherwise "ideal" basement for a model railroad empire. 

David

I would advise checking ceiling height.  I have a semi-permanent crease in my forehead from the area where the heating ducts run.  My layout shares a room with my workshop and I can only stand up straight on one side of the layout.  I thought of going with a U shaped layout but that would have meant I couldn't have stood up straight in 90% of the open area. 

Kevin

The REAL issue is water!  Any moisture that gets into the basement must be controlled and eliminated if possible.  If the house is new enough then there should be a modern water-proofing system around the foundation.

Get a home inspection, but be sure to go through the house and basement with the inspector.  Ask questions and more questions,  The qualifications and experience required by states varies. 

Jan










Most are not a Mike Holmes.

David,

The houses that I am talking about in this new community have the old cinder block basement construction.  So what I am dealing with is the choice of a solid poured concrete basement or one constructed of old style cinder blocks.

I am somewhat familiar with CONCRETE block construction, however, I have not come across that basement fabrication in my search for a new home in the area that I am looking at.

Thanks to all for their input so far.

Steve

Cinder block would tend to date the house.   Most construction 1960 to present would have concrete cast block. Cinder block tends to be more pourous, a black, gritty dust when drilled, and soft in comparison to aged concrete block, which can be difficult to drill.   Today, in Pennsylvania, under the UCC, Universal Construction Code, the block walls have to be rodded and concrete poured in the block cells. Not all the cells, but substantial, to increase structural strength.  By adding this detail and expense, a lot of builders just go with the poured concrete wall v.s. the block lay-up. 

Moisture control has a lot to do with the outside membrane installation and proper drainage from the footer area as has been mentioned.

Also most homes technically don't heat or air condition the basement area.  The HVAC systems were designed to heat the living space above.  There may be a few vents to the basement area.    Appropriate climate control in the basement is a whole other discussion, that relates to a train layout, or for that matter converting the area to living space. This may require additional mechanical equipment.    

Mike CT,

I agree with you with regard to cinder block construction "dating the house".  But these are new houses, many of which are yet to be built.

Steve

A lot of newer poured foundations are done with foam panel forms which remain in place. They act as a moisture barrier and add insulation value. In addition the basement floor is poured on the ground surface rather that digging a hole. Then fill is brought in to grade up to the first story. Ground water issues are eliminated.

Pete

I've lived in houses with block walls and poured concrete.

Were I to build a home, it would be with poured concrete walls in the basement.

Crushed stone under the basement floor is a must.

Exterior waterproof membrane is a must.

Proper grading and adequate distance from the home's siding and the ground is a must.

The system Norton described sounds interesting.

And add my name to the list of folks who mentioned making certain the basement will have enough headroom.

When one of my buddies custom built his home, he put foam insulation under his basement floor and on the outside of his poured concrete walls. After almost thirty years, his basement is dry and warm. The insulation has not created any negative issues.

Check out the post I made last night, "Ive been working on the railroad room".  There are a few pictures of my construction project.  My basement is poured walls and there is a french drain around the edges of the slab.  This is just a 1/2 inch gap between the walls and floor to keep the water from getting onto the floor and keep it in the sump.  My walls were covered in insulation and I just set the walls out from the wall a couple inches.  The big thing to look for is ceiling height.  Poured walls may not be as tall and the finished room may have some head space issues.  You will find that the floor is not level and you will need to level everything from the top down if you want to install dry wall.  I didn't put the drywall all the way down since the bench work is going to cover that area.  Feel free to contact me if you have any questions.  I hung 45 sheets of drywall in the finished side of the basement befor I decided to build a train room.

Jimiller320,

Thanks for this info!

I have decided to look carefully the next time the wife and I visit these new communities to see exactly what they are doing regarding basement construction.  I'll ask a lot of questions and hopefully actually visit a job site to see firsthand the construction techniques and materials that they are using.  Hopefully that will happen next week; this week is getting my house in order to put it on the market.

Steve

Consider the poured concrete foam.

A few additional ideas:

Consider having the wall tall enough to provide 9'6" from the floor to the bottom of the joist or truss cord.  This will permit adaquate space for HVAC and dropped ceiling yet provide a standard 8' finished ceiling height.

Consider proper grade/swale design with generous roof over hang and down spout runoff.

Both an external and internal footer french drain with 120 utility and 12 volt Watchdog back up battery system.  Check the Granite nature of your area for radon issues.  If there are radon issues an extra sump with a sealed top for a remediation pump is a handy extra, and cheap to add at this point.

If the floor is not poured at this point you may wish to run some electrical conduit. 

In our last place I had a 3 step down - 3 step up short depressed passage instead of a duck under for the RR. An idea I picked up at Cherry Valley RR club.  Cost a few hundred extra while under construction.

Stair case position will be very important. 

All mechanicals need to be positioned to accomadate benchwork.

Be careful where any interior meters or valving is placed.  Make sure the electrical service entrance will not interfere with benchwork or traffic.

Tankless waterheaters will help cleanup the floor space and get rid of that ugly H2O tank.

Back up check valve for basement drain, toilet. 

Make sure any ceiling mounted shut off valves will not be positioned over the layout.

Can the electrical service entrance/circuit breaker box be on the first floor anywhere?

Now is the time to have engineering adjust beam size for needed support column location. 

Make sure any water treatment access will be doable.  

If you will be in this place during your senior years consider making it ADA compliant.  Wider doorways, level finished floor surfaces, higher commodes.  All special touches are must cheaper now. tt

Slightly OT but I thought the perfect house for a train nut would be built on a hill so that the basement would have a walk in ground level access on one side. NO STAIRWAY! You can find plenty of them even in New York State.

Pete

Pay especial attention to electrical outlets and lighting...I had overhead flourescents

installed, but wish I had doubled them...and same for round the wall electrical

outlets...I'd want one every 10 feet...so outlet location doesn't dictate transformer

locations.

 Check to see if its now code that a basement be poured concrete as some communities have adapted these by-laws.

 Having an older house (1958)my house has cement block walls.They are alright,but it's what they did at the time.

 And do check for how many outlets are or could be installed as you may need several for your layout.And check how many additional breakers the box has for future reference.

 If you buy an already built house, ask what their building technique was when constructing the basement,drains,sump pumps,outer barrier (gravel,french drain,insulation,etc.).Sounds like a lot to ask but as you well know a home is a big investment that after the facts is hard to deal with  and costly.

  Also check the ceiling for places to install tract lighting and the feasibility of running the wires to them .

 And as mentioned, check where the plumbing and shut offs run.

 coloradohiraile you have the same problem I have although my basement was already finished.Not enough lights or outlets makes it rough trying to plan a layout.

If you have a block or concrete foundation wall a coat of Thoroseal will help minimize the moisture problem. It is available at Lowes and Home depot and is applied to the interior side of the walls. I don't suggest using it to stop running water just to prevent dampness.

My basement is poured, reinforced concrete and features a walkout door to the patio. The exterior walls were sealed and I have not had any water problems (yet) in this 13 year old house. I, too recommend Thoroseal. (sp?)

Now...I wish I could say the same for the windows I've replaced and now.....a garage door has to be replaced. UGH!    Tom in pgh