Radon Mitigation in Derry, NH

A radon mitigation system gives the gas a way out of your house that is not through your living space. Pipe, fan, sealed entry points, and a way to confirm it is working. If you have a test result in hand and you are in Derry, we can look at it.

What radon actually is, without the scare

Radon is a gas that comes up out of the ground and gets into houses through the lowest level. You cannot smell it or see it. At high enough levels over long enough it is genuinely bad for you, which is why testing exists.

The reason we lead with testing rather than selling: your neighbour’s number is not your number. Houses fifty feet apart test differently. Get your own.

How the system works

The common approach is sub-slab depressurization. We core the slab, put a pipe into the material under it, run that pipe out and up, and put a fan on it. The fan pulls a slight vacuum under the slab so the gas goes up the pipe instead of into the basement. Then we seal the obvious entry points, the floor wall joint and any open sump, so the system is pulling from under the slab and not from your basement air.

Crawl spaces work a bit differently. The membrane becomes part of the system and we draw from underneath it.

Testing before and after

We test, we install, we test again. That second test is the whole point, and you should insist on it from anyone you hire.

603 holds a state radon measurement certification, RMS-113966.

What we will not promise you

We will not guarantee a specific radon number unless we put that number in writing for your house.

Plenty of outfits will promise you a level over the phone. We would rather test your house, install the system, test again, and show you where it actually landed. If a specific result matters to you, and for a real estate closing it usually does, get it in writing before the work starts. From us or from anybody else.

The warranty

Radon mitigation carries a 10 year warranty on system integrity and components. That covers the system. It is not a guarantee of a radon level, for the reason above.

Questions we get

My house is new. Do I still need to test?
Yes. Construction age does not tell you what is under the slab.

Is the fan loud?
You should hear a low hum at most. If a system is noisy or rattling, something is wrong with it and it is worth a call.

Does it run all the time?
Yes, continuously. Turning it off means it is not doing anything.

What about radon in water?
That is a separate test and a separate system from the air side. If you are on a private well it is worth asking about.

I am selling. How fast can this happen?
Tell us the closing date when you call. Most installs are a day.

Reading your test result

Situation	What it means	What happens next
Short-term test came back high	A snapshot, and worth acting on	Confirm, then look at the house for a system layout
Two tests disagree	Normal. Radon moves with weather and season	Longer test, or treat the higher reading as the planning number
Buyer or seller needs a number	There is a deadline attached	Tell us the closing date when you call
Finished basement, no test yet	People spend hours in that room	Test before you spend anything else on the space
Crawl space rather than a slab	Different system design	The membrane becomes part of the system
On a private well	Water is a separate pathway from air	Separate test, separate system if needed

How the job runs

It starts with a number. If you already have a test result, bring it. If you do not, that is where we begin, because there is no sense designing a system for a house nobody has measured.

Then somebody looks at the house. Where the slab is, where the pipe can run, where the fan can sit so you are not listening to it in the room above. That layout is most of the job and it is why we do not quote it over the phone.

On install day the slab gets cored, the pipe goes in and runs out and up, the fan goes on it, and the obvious entry points get sealed so the system is pulling from under the slab rather than out of your basement.

Then we test again. That second test is the point of the whole exercise, and you should insist on it from anybody you hire, us included.

What the state’s map records under Derry

Derry has a proper surficial geologic map, published by the New Hampshire Geological Survey in 1985 as GEO-89 at 1:24,000, and it is more detailed than most towns get.

That map records twelve mapped units (New Hampshire Geological Survey, Surficial Geologic Map of the Derry Quadrangle, Rockingham County, Gephart, 1985). Among them are alluvium, swamp deposits and stream terrace deposits from the Holocene, and a set of glacial lake deposits including Glacial Lake Auburn, Glacial Lake Cohas Brook, Glacial Lake Wilson and Glacial Lake Derry, plus the Chester glacial stream deposits.

Glacial lake deposits matter to anybody with a basement. Material that settled out in still water tends to be fine, and fine material holds water rather than letting it pass.

One honest limit, and we would rather state it than gloss it: the Derry quadrangle covers roughly two-thirds of the town, not all of it. So “Derry’s geology is X” is not a sentence anybody should write, including us. Part of the town is on that sheet and part is not.

Soils and how they drain

The USDA NRCS soil survey data for the town is aggregated by dominant component, and that carries its own caveat worth knowing: a component-percentage weighting gives a materially different drainage picture than a dominant-component one. Two legitimate methods, two different numbers. We are not going to pick whichever one sounds better.

Why we lead with the caveats

Because the alternative is a contractor telling you what is under your house based on a map that may not even cover your side of town.

Derry is one of the closest towns to our shop in East Kingston, so we are through there constantly and we are not guessing about the drive. What is under a specific foundation on a specific street is a different question, and the only honest way to answer it is to come and look.

That inspection is free, and you get a written scope out of it rather than a number over the phone.

Glacial lake ground, and what it tends to do

Four of the twelve units on the Derry sheet are glacial lake deposits. Material that settled out of standing water is finer than material dumped by a fast meltwater stream, and fine material is slow to give water up once it has taken it on.

That is a general property of the material, not a prediction about your foundation. Plenty of houses sit on fine ground with dry basements, usually because the water around them has somewhere better to go.

The stream terrace and alluvium units on the same map tell you where water has historically run and left material behind. Those are the low routes through town, and low routes stay low.

What our customers say

I realized my radon mitigation fan was no longer functioning efficiently so I called 603 basement Solutions. They answered my request very quickly and scheduled an appointment for someone to come out and check out and replace the fan if needed. He was prompt, came when the appointment was and I was lucky he had the replacement fan with him. The work was all done in a short period of time and I couldn’t have been more satisfied.

Mary Pelletier, Google review, 5 stars

That is one of more than 240 Google reviews. We would rather you read them than take our word for anything on this page.

Related pages for Derry

Book a free inspection in Derry

Somebody comes out, looks at the actual space, and tells you straight what it needs and what it does not. You get a written number for a defined scope. No two hour pitch, because we would rather be at the next house.

If you are looking for a team that isn’t going to treat you like another number, we would be happy to give you an estimate free of charge. We don’t cut corners. We stand behind our work. We care.

Call 603-610-1770 or book your free inspection. We cover Derry and the surrounding towns from our shop in East Kingston, New Hampshire.

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