How to properly care for a porcelain sink

Q. Recently we had a quartz countertop and new undermount porcelain sink installed in our bathroom. In order to determine the best and safest cleaning product to use on the sink, I searched the internet for suggestions on appropriate cleaning products. Unfortunately my search resulted in conflicting suggestions. I previously used Scrubbing Bubbles on my cultured marble sink and countertop. According to the can, this product is safe for porcelain. What suggestions can you provide to clean and maintain the quality of the porcelain finish?

A. Scrubbing Bubbles is fine. So is a mild white vinegar/lemon juice/water solution, if you prefer a nonchemical alternative.

If you need to "scrub" the sink, a little baking soda sprinkled on the sponge is very kind to the surface.

Any nonabrasive kitchen cleaning product should be OK.

Q. I installed an attic vent fan years ago. It's clear that they aren't energy savers, but when we had whole house air-conditioning installed, the only place to put the chiller was in the attic. (We have hot water - hydronic- heat - no ducts!) I have the fan set at 85 degrees, was thinking of raising it to 95-100. The roof is concrete tiles with air space underneath the tiles and the house has no soffit vents. The result is that the air spaces between the bottom of the tiles and top of the decking can be used to move air to keep the attic cooler.

I don't have the details of the vent system handy. But the idea seems to be providing an opening for air to enter at the lower tiles and exit from the upper tiles.

Finally, we have had sparrows nesting between the bottom of the tiles and roof decking so we know (or should have known) that it was not extremely hot under the tiles.

It is nearly impossible to work in the area. Part of the attic is adjacent to the upstairs bedrooms and part is above the upstairs bedrooms.

The installers put insulation around most of it, but there isn't enough space to "box off" the chiller. Long story short, the intent is to keep the chiller box at a reasonable temperature without remodeling the entire attic or replacing the "character" cement tile roof. If you want to suggest an alternative approach that doesn't require remodeling something it would be appreciated.

Last comment, I did some repair work on the roof and pulled a permit.

(Our village) inspector wasn't going to release the permit because we didn't install a ridge vent. I've never seen one for a tile roof. Is there such a thing?

A. The building inspector should know that a ridge vent without an equivalent net free ventilation area (NFVA) in the soffits is not effective. Interesting that the building inspector did not mention that fact and insist on the installation of soffit vents as well.

From your description, it sounds to me as if you need neither ridge nor soffit vents. You seem to have enough ventilation as it is to keep the attic from overheating. The sparrows are like the canaries in testing wells.

But if you need to install a ridge and soffit venting system to get your permit, and if your roof has overhangs, and there is an unobstructed air space between the soffit and ridge vents, continuous soffit vents could be installed. However, if there is no such air space, it would be useless to install soffit vents.

There are ridge vents for both corrugated and flat concrete tile roofs.

I am familiar with the Lomanco TRV-4 TileRidge for use on corrugated tile roofs ([http://]www.lomanco.com/tileridge trv4) and the LOR9-4 for use on flat tile roofs (www.lomanco.com/lor9-4-on-flat-tile-roof).

Lomanco also makes intake vents for both types of tile roofs, which they claim are fully effective in providing the NFVA needed to match that of their ridge vents.

There are other suppliers of venting systems for tile roofs. Your local building-supply houses may either carry other brands as effective as the Lomanco products or order them for you.

If it is determined that the attic fan is absolutely needed to keep the attic cooler, you should make sure that there is adequate intake air to satisfy its CFM rating in the attic; otherwise it is not working as effectively as it should unless it is able to rob the additional makeup air it needs from the conditioned air below the attic - a waste of energy.

The problem I see is that there is no opposite gable since this partial attic space is backing up to bedrooms. The additional makeup air may have to be provided through the roof as far away from the fan as feasible. It is much better to avoid using the fan. Do you really need it?

You mention the cramped space, but if it is possible, it would be very helpful to staple special reflective aluminum foil to reflect the sun's heat back up to the roof.

Q. You have helped me on two occasions and I'm hopeful you can help again. The top of our coffee table is wood with black slate inlays. Glasses filled with ice water or a cocktail have been placed on the slate and have left white rings. I have rubbed Vaseline on the slate but that doesn't help.

Any suggestions?

A. According to my expert contact on stains and other problems affecting stone, slate, granite, marble and more, buff the stains with 0000 steel wool.

If that does not remove the water stains, please let me know, and if you can send a photo, I'll dig deeper into it.

From a Massachusetts reader: "Several times in the last few weeks you have had questions on "black specks" in people's water. This may not be the only answer, but it is an answer that you did say was a possible cause in one answer you gave. We had a similar problem after the town added a new water tank near our house. I called the Water Department, DPW, and it was explained that they were using a chemical that treats the inside of the distribution pipes. Do not know what, didn't ask the name of the chemical. I was told that it does not show up in every hose, but since we are near the storage tank, the water is pumped uphill past our house, and flows down past our house. At times, dynamics of the changing water flow near our house may be an area that causes to have a still/calm area in the pipes, we will get the chemical specks. There is another area in the system, closer to the wells/pumps, that does the same. We use a Brita filter for our drinking water. That is where we see the specks still, but once or twice after they put the new storage tank into service, we saw the specks in the toilets also. A neighbor said he had them also. If anyone who is affected, wants a better explanation, they should call their DPW to get a full explanation.

Hope this helps someone to not be overly concerned."

• Henri de Marne, a former remodeling contractor turned columnist and consultant, is the author of "About the House with Henri de Marne" (Upper Access Publishing). He continues to take questions from readers for this column and his website, www.henridemarne.com. Email questions to aboutthehouse@gmavt.net.